What's the terminology that is used for receipt? Something like:

Received £XXXX From XXX on XX-XX-XX

For "my car" reg no XX 00 XXX.

Sold as seen, no warranty supplied or implied.

Signed
Dated

never given a receipt for a private sale. they give me the cash, I give them their part of the V5 and the keys.

http://www.theaa.com/motoring_advice/car-buyers-guide/cbg_sellerscontract.html

Sounds about right. There's no come back with a private sale no matter what anyhow. Might be worth writing private sale on there…

I print out a "receipt" for both me as the seller and they as the buyer – we then just add the date, reg and names/signatures.