There is a Gracie Academy affiliate in Bradford. It teaches BJJ/GJJ, but the emphasis is first and foremost on "self-defence" skills.
If Bradford is too far for you to go, there might be a Gracie Barra class in York still. There is a contact address for them on here:http://www.grapplingartsassociation.org/...0&Itemid=52
This place in York offers BJJ classes too it seems:
This site has a list of Judo clubs in Yorkshire and Humberside:http://www.yhjudo.org.uk/
To be honest with you, Judo is almost always taught first and foremost as a "sport". It still has a ton of skills that are applicable in security and law enforcement though, but bear in mind a lot of folks in the club are focused on training for sport.
BJJ, though mainly a sport, is still more likely to teach moves with an emphasis on "self defence" than Judo.