diff --git a/src/main/java/org/icatproject/icat/client/ICAT.java b/src/main/java/org/icatproject/icat/client/ICAT.java
index 3aff4ab..7a9667c 100644
--- a/src/main/java/org/icatproject/icat/client/ICAT.java
+++ b/src/main/java/org/icatproject/icat/client/ICAT.java
@@ -18,6 +18,7 @@
 import java.util.Map.Entry;
 
 import javax.json.Json;
+import javax.json.JsonArray;
 import javax.json.JsonException;
 import javax.json.JsonReader;
 import javax.json.JsonString;
@@ -593,8 +594,8 @@ String searchInvestigations(String sessionId, String user, String text, Date low
 	}
 
 	String searchInvestigations(String sessionId, String user, String text, Date lower, Date upper,
-			List<ParameterForLucene> parameters, List<String> samples, String userFullName, String searchAfter, int limit, String sort, String facets)
-			throws IcatException {
+			List<ParameterForLucene> parameters, String userFullName, String searchAfter, int maxCount, String sort,
+			JsonArray facets) throws IcatException {
 		URIBuilder uriBuilder = getUriBuilder("search/documents");
 		uriBuilder.setParameter("sessionId", sessionId);
 		ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -616,24 +617,19 @@ String searchInvestigations(String sessionId, String user, String text, Date low
 			if (parameters != null && !parameters.isEmpty()) {
 				writeParameters(gen, parameters);
 			}
-			if (samples != null && !samples.isEmpty()) {
-				gen.writeStartArray("samples");
-				for (String sample : samples) {
-					gen.write(sample);
-				}
-				gen.writeEnd();
-			}
 			if (userFullName != null) {
 				gen.write("userFullName", userFullName);
 			}
+			if (facets != null) {
+				gen.write("facets", facets);
+			}
 			gen.writeEnd();
 		}
 
 		uriBuilder.setParameter("query", baos.toString());
 		uriBuilder.setParameter("search_after", searchAfter);
-		uriBuilder.setParameter("limit", Integer.toString(limit));
+		uriBuilder.setParameter("maxCount", Integer.toString(maxCount));
 		uriBuilder.setParameter("sort", sort);
-		uriBuilder.setParameter("facets", facets);
 		URI uri = getUri(uriBuilder);
 
 		try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
@@ -689,7 +685,7 @@ String searchDatasets(String sessionId, String user, String text, Date lower, Da
 	}
 
 	String searchDatasets(String sessionId, String user, String text, Date lower, Date upper,
-			List<ParameterForLucene> parameters, String searchAfter, int limit, String sort, String facets) throws IcatException {
+			List<ParameterForLucene> parameters, String searchAfter, int maxCount, String sort, JsonArray facets) throws IcatException {
 		URIBuilder uriBuilder = getUriBuilder("search/documents");
 		uriBuilder.setParameter("sessionId", sessionId);
 		ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -711,14 +707,16 @@ String searchDatasets(String sessionId, String user, String text, Date lower, Da
 			if (parameters != null && !parameters.isEmpty()) {
 				writeParameters(gen, parameters);
 			}
+			if (facets != null) {
+				gen.write("facets", facets);
+			}
 			gen.writeEnd();
 		}
 
 		uriBuilder.setParameter("query", baos.toString());
 		uriBuilder.setParameter("search_after", searchAfter);
-		uriBuilder.setParameter("limit", Integer.toString(limit));
+		uriBuilder.setParameter("maxCount", Integer.toString(maxCount));
 		uriBuilder.setParameter("sort", sort);
-		uriBuilder.setParameter("facets", facets);
 		URI uri = getUri(uriBuilder);
 
 		try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
@@ -905,7 +903,7 @@ String searchDatafiles(String sessionId, String user, String text, Date lower, D
 	}
 
 	String searchDatafiles(String sessionId, String user, String text, Date lower, Date upper,
-			List<ParameterForLucene> parameters, String searchAfter, int limit, String sort, String facets) throws IcatException {
+			List<ParameterForLucene> parameters, String searchAfter, int maxCount, String sort, JsonArray facets) throws IcatException {
 		URIBuilder uriBuilder = getUriBuilder("search/documents");
 		uriBuilder.setParameter("sessionId", sessionId);
 		ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -927,14 +925,16 @@ String searchDatafiles(String sessionId, String user, String text, Date lower, D
 			if (parameters != null && !parameters.isEmpty()) {
 				writeParameters(gen, parameters);
 			}
+			if (facets != null) {
+				gen.write("facets", facets);
+			}
 			gen.writeEnd();
 		}
 
 		uriBuilder.setParameter("query", baos.toString());
 		uriBuilder.setParameter("search_after", searchAfter);
-		uriBuilder.setParameter("limit", Integer.toString(limit));
+		uriBuilder.setParameter("maxCount", Integer.toString(maxCount));
 		uriBuilder.setParameter("sort", sort);
-		uriBuilder.setParameter("facets", facets);
 		URI uri = getUri(uriBuilder);
 
 		try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
diff --git a/src/main/java/org/icatproject/icat/client/Session.java b/src/main/java/org/icatproject/icat/client/Session.java
index 1f704e7..4abc364 100644
--- a/src/main/java/org/icatproject/icat/client/Session.java
+++ b/src/main/java/org/icatproject/icat/client/Session.java
@@ -6,6 +6,8 @@
 import java.util.List;
 import java.util.Map;
 
+import javax.json.JsonArray;
+
 /**
  * A RESTful ICAT session.
  * <p>
@@ -439,7 +441,7 @@ public String searchInvestigations(String user, String text, Date lower, Date up
 	 *                     String representing the last document of a previous
 	 *                     search, so that results from this search will only
 	 *                     include results from after the document
-	 * @param limit
+	 * @param maxCount
 	 *                     The maximum number of results to return.
 	 * @param sort
 	 *                     String representing a JSON object which contains key
@@ -458,11 +460,10 @@ public String searchInvestigations(String user, String text, Date lower, Date up
 	 *                       For various ICAT errors.
 	 */
 	public String searchInvestigations(String user, String text, Date lower, Date upper,
-			List<ParameterForLucene> parameters, List<String> samples, String userFullName, String searchAfter,
-			int limit, String sort, String facets)
-			throws IcatException {
-		return icat.searchInvestigations(sessionId, user, text, lower, upper, parameters, samples, userFullName,
-				searchAfter, limit, sort, facets);
+			List<ParameterForLucene> parameters, String userFullName, String searchAfter, int maxCount, String sort,
+			JsonArray facets) throws IcatException {
+		return icat.searchInvestigations(sessionId, user, text, lower, upper, parameters, userFullName,
+				searchAfter, maxCount, sort, facets);
 	}
 
 	/**
@@ -523,7 +524,7 @@ public String searchDatasets(String user, String text, Date lower, Date upper, L
 	 *                    String representing the last document of a previous
 	 *                    search, so that results from this search will only include
 	 *                    results from after the document
-	 * @param limit
+	 * @param maxCount
 	 *                    The maximum number of results to return.
 	 * @param sort
 	 *                    String representing a JSON object which contains key value
@@ -541,8 +542,8 @@ public String searchDatasets(String user, String text, Date lower, Date upper, L
 	 *                       For various ICAT errors.
 	 */
 	public String searchDatasets(String user, String text, Date lower, Date upper, List<ParameterForLucene> parameters,
-			String searchAfter, int limit, String sort, String facets) throws IcatException {
-		return icat.searchDatasets(sessionId, user, text, lower, upper, parameters, searchAfter, limit, sort, facets);
+			String searchAfter, int maxCount, String sort, JsonArray facets) throws IcatException {
+		return icat.searchDatasets(sessionId, user, text, lower, upper, parameters, searchAfter, maxCount, sort, facets);
 	}
 
 	/**
@@ -650,7 +651,7 @@ public String searchDatafiles(String user, String text, Date lower, Date upper,
 	 *                    String representing the last document of a previous
 	 *                    search, so that results from this search will only include
 	 *                    results from after the document
-	 * @param limit
+	 * @param maxCount
 	 *                    The maximum number of results to return.
 	 * @param sort
 	 *                    String representing a JSON object which contains key value
@@ -668,8 +669,8 @@ public String searchDatafiles(String user, String text, Date lower, Date upper,
 	 *                       For various ICAT errors.
 	 */
 	public String searchDatafiles(String user, String text, Date lower, Date upper, List<ParameterForLucene> parameters,
-			String searchAfter, int limit, String sort, String facets) throws IcatException {
-		return icat.searchDatafiles(sessionId, user, text, lower, upper, parameters, searchAfter, limit, sort, facets);
+			String searchAfter, int maxCount, String sort, JsonArray facets) throws IcatException {
+		return icat.searchDatafiles(sessionId, user, text, lower, upper, parameters, searchAfter, maxCount, sort, facets);
 	}
 
 	/**