to not pay until work is done

[macdaddydoodah]

Right... Currently getting external wall insulation via green deal home improvement fund. Voucher, worth 75% of total cost expires 1st feb and is not extendable.
Work is nearly done but there is snagging list. Builder wants me to sign off work, they will then send final invoice which I must pay in full before they send off paperwork which fulfills voucher and I get money and they will finish off work later.
However, so far nothing has been done on time so rather than them sending it off (or not, loosing me a whopping 6k) I propose we sign paperwork tomorrow, they give me final invoice, I pay most but not all, I send paperwork off, they finish off work, I pay remaing £ to them.
They say this is not poss but green deal admin says this is fine.
Aibu? And wwyd?

[wowfudge]

Do as you suggest. Stand firm. They want to get paid, this is how they get paid.

[GhoulWithADragonTattoo]

If Green Deal say is fine (I'd get in an email for record) then it seems most sensible way to proceed.