I was going to suggest Phil Joy in Hatfield so if you google it you might find where he is & a phone number.
Or there's these people
http://www.pipercams.co.uk/pipercams/www/index.phpI used a company in Farnborough Kent right on the A21 to reprofile my CB750F2 for fast road profiles but it wouldn't time up correctly due to uneven heights between the base circle & the lobe tip. I took it back, they placed it into their jig & confirmed my doubts about what they'd done. They did modify my XL185/200 & XL250SA cams ok though, shaving about 0.5mm off the base circle, giving me slightly more lift & duration.