Structure of setting up a new charity

I have been asked to help set up a local small charity that will raise around £20k per year through selling and fundraising etc so it is very small and the trustees are all family members, not open to the public.

What structure do you suggest. I looked at the CIO but need assistance with the trust deed etc. I believe with CIO you can register with Charities Comission and do annual accounts but no need to file at Companies House.

Any help would be appreciated