Arranging £££ for uk car purchase

Thinking of taking a trip over to england to buy a car. A bit fuzzy as to the best way to organise cash in the event of buying.

I don't want to change cash without knowing I am going to buy and how much I need. Just looking for a cheap runaround - so would be just under the €3000 visa debit card limit. Can I just buy off one of the high street banks over there using visa??

Not as easy as you suggest over there. Depending on where you are going it might be best have your Bank here, to advise the same Bank with the nearest branch to where you are going of youe intentions and your possible requirements.