Try Cabair - they are looking for instructors at the moment, pay isn't bad either.
White Waltham may have a vacancy in a few weeks - very nice club to instruct (and fly) at (sadly I missed a job there).
Captain Cute - not off to East Herts are you?
If you can get hold of the Where to Fly issues of Pilot and Flyer for this year ring all the numbers in there, and send cvs to all the addresses - worked for me!!