URL Relations with ampersands in the URL aren't being escaped in XML returned by the WebService API.

Example:
http://musicbrainz.org/ws/2/artist/f5d51e0f-323e-46de-96ce-d427fd4b124c?inc=url-rels+artist-rels+label-rels

Which is the artist information for George Formby:
http://musicbrainz.org/artist/f5d51e0f-323e-46de-96ce-d427fd4b124c/relationships

What has this URL associated with him:
http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=1228

Couple of other examples:
http://musicbrainz.org/artist/b625448e-bf4a-41c3-a421-72ad46cdb831/relationships
http://musicbrainz.org/artist/c7356af9-9ea6-4a78-a55b-c73775716312/relationships

This is causing 500 errors on the BBC Music site:
Music - John Coltrane: http://www.bbc.co.uk/music/artists/b625448e-bf4a-41c3-a421-72ad46cdb831
Music - Charlie Parker: http://www.bbc.co.uk/music/artists/c7356af9-9ea6-4a78-a55b-c73775716312
Music - George Formby: http://www.bbc.co.uk/music/artists/f5d51e0f-323e-46de-96ce-d427fd4b124c