You can make your own, I am not sure that any of them are actually legally binding, although the terms of the agreement will be taken into consideration in any subsequent court case.
I would still use the BHS agreement as a basis for yors if possible
Hey, some advice (im a trainee solicitor on my 4th year so have a little info on this sort of stuff) You can make your own but if it doesnt encompass several areas then it wont be legally binding. Fot it to be legally binding consideration from both parties needs to be shown as well as being very clear and consise- one slip in terms of clarity and you could find that it could be interpreted in several ways and therefore not legally binding in that sense- basically a good contract that "works" is complex and needs careful drafting. If you need help PM me and i can pass on a copy of one that can give you ideas on what you need.
You can draw up your own contract without any real problem Decide exactly what you want & exactly what the other party wants. Then if you are both happy with your decisions then commit it to paper. Do not feel you have to use high brow language & technical terms. You can use every day normal speech, that way everyone understands what the contract says. When it is written out read it over several times to be sure it actually says what you want & what you have written cannot be construed another way or be taken to mean somthing other than what you wanted. They when everyone is happy both sign & date it with a couple of witnesses present. who will also sign. Just give everything alot of thought & it should be ok. As a previous poster has said, if you have access to someone elses agreement it may give you a little inspiration on how to go about it.
Good Luck