Not sure if you're still looking for a class (stumbled on this thread while Googling an unrelated question), but I do Shotokan Karate in Whitstable (Tuesday) and Faversham (Thursday). I live just outside Sittingbourne myself. Not sure if it's your thing but we have a really well established and friendly club. We offer 4 lessons free for beginners. http://www.shotokankaratekent.co.uk/