Oh, and the car was registered on our name. Buyacar are holding onto the document but at least we are the first owners

How can they hold onto the document? If the car is registered in your name then the V5 is sent to the registered keepers address.

maybe they wont then....... Confused

there is no requirement to be the owner of a vehicle to insure it.

if bengie bothered to read a v5 he would notice its carries the wording "this document is not an indication of legal title"

as of course any car on finance is owned by the finance company. .....