There are several lenders who'll lend for GA buyers. Mostly, they're classic car lenders who have a bit of GA knowledge. I can dig out some emails if you want as I looked into doing this as a sideline last autumn. I decided not to as I couldn't see what would be in it for me as a 'lead'.
I've always worked on the basis of buying outright if it's for pleasure and paying for finance if it's a business (tax efficiency and balance sheet etc etc).
So, if you want a £30k Bulldog, you can have one, but you'll need a 25% deposit.