Quite a few years ago I used to have personal loans to help buy cars .
At no point did I ever have to prove to the lender that I had actually bought a car.
So a loan was paid off and I perhaps some time later started another loan with the same lender . I came to a time when instead of changing the car using the loan I bought a boat.
Therefore if its a personal unsecured loan you can buy anything with the money. All the lender asks is you pay it back, with interest of course , according to the agreement.
I expect such a loan would be limited in amount the £1 to £25k bracket and paid back over 1 to 7 years - eg Co-Op bank
https://www.co-operativebank.co.uk/products/loans/