PREFIX myfn: <java:com.ldodds.sparql.> 
PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX ad: <http://schemas.talis.com/2005/address/schema#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?title ?lat ?long
WHERE 
{
  ?x dc:title ?title;
     geo:lat ?lat;
     geo:long ?long.
  OPTIONAL { ?x foaf:homepage ?homepage. }
  FILTER ( myfn:PointInBoundingBox("51.451455", "-2.602384", "52.21823", "0.129068", ?lat, ?long) )
}