[maxehmookau]

I wasn't specific enough, sorry. By "cash" I meant "not finance". It's very unusual to turn up to a car dealership in the UK with a suitcase full of £20 notes (and would probably ring alarm bells for money laundering).

Usually dealerships insist on a bank transfer. Although, pro tip, if you can agree to paying a deposit with a credit card then the entire car purchase should be covered under Section 75 protection if the car is not sold as advertised.