You could ring Somerford Park.
They are Cheshire, but just off the M6 - http://www.somerfordpark.co.uk/
They do clinics and summer camps.
We also have an Event trainer in Yorkshire (Leeds area) called Tim Pearson. He's a group 3 trainer and should know of Clinics in the area. I'll try and send you his number as he advertises in our local paper - I don;t have a copy to hand at present.
Failing that try a couple of the bigger venues and see if they've got anyone visiting.