Fix URI in sample data (#3)

Author: afizzycola

Sample Data/hospital.ttl

@@ -1,6 +1,6 @@
 @prefix 				    rdf: 				        <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix 				    rdfs: 				        <http://www.w3.org/2000/01/rdf-schema#> . 
-@prefix 				    ies: 				        <http://ies.data.gov.uk/ies4#> . 
+@prefix 				    ies: 				        <http://ies.data.gov.uk/ontology/ies4#> . 
 @prefix 				    data: 				        <http://data.gov.uk/testdata#> .
 @prefix 				    iso8601: 			        <http://iso.org/iso8601#> .