We are having our self build built by a main contractor. He has priced the build up for us, which we are happy with. We now need a contract ASAP. He has provided a JCT building contract which I think is for larger more complex works than our job. We do not have a contract administrator which is mentioned in the contract.

would a home owner contract or intermediate contract be better?

its just  straight forward build cost approx 300k

please help as new to all this

This podcast might be worth a listen. If memory serves, I recall that Ruth Butler (an architect) described the contracting arrangements she used for her build, which I thought were rather good.

 

https://www.houseplanninghelp.com/hph177-redeveloping-a-brown-field-site-for-a-contemporary-home-with-ruth-butler/