Does anyone know of where I can get a subcontractor agreement that is compliant with ICAEW practice management regulations?
I know this is stating the obvious but have you tried contacting ICAEW to see if they can point you in the right direction.
Alternatively I have a standard AAT subcontractor agreement which I can email you if you PM me your email address.
ICAEW Subcontractor Helpsheets
you can find these ICAEW helpsheets at http://www.icaew.com/en/members/advisory-helplines-and-services/practice-helpsheets
as long as you are a member of ICAEW [you'll need to be logged in]