HMRC have simply said
10.1 Recovering VAT incurred on community projects, particularly work to village halls
If you’re a local authority, you may:
•agree with a voluntary group to set up a project fund into which any funds raised locally and any grants received by the voluntary group will be paid
•use this fund to make the purchase or pay for the work on behalf of the voluntary group
But these funds do not belong to you and so you cannot recover the VAT incurred.