VW polo - Cash in lieu settlement - Polo2008

My partner is on my insurance as the named driver, both of us never claimed in 25+ years . He was driving my old polo and a Polish lorry drove into the rear door, owing to the language barrier insurance having difficulty proving liability though at roadside lorry driver did say he didn't see him (Lh drive).

As it needed a new door it was stated a write off but we since just bought a new door and had it fitted as they were dragging their feet. We wanted to keep this car as I'd had it from almost new it's been fully serviced well looked after only 58k Miles. Door replacement purely cosmetic we were fortunate enough to find one exactly the same colour.

So we have been offered a cash settlement in lieu less salvage but I'm unsure where I stand on this having not been in this situation before. It's for more then our repair cost.

Thing is what happens? we have made it clear we are keeping the car. I'm inclined to forget the whole thing... Should I as the excess situation is difficult and will affect our insurance in future.

Do we get to keep the car if we accept this payment? Do they need receipts for our repair? What category will it be and how will it affect future insurance policies, ie will some not insure us?

Minefield! anyone with any advice please?