Usually, card transactions in the UK are around 2,5%. Sometimes a bit lower. Depends on getting the best Deal.
With comparison websites, you immediately get a couple of quotes of the bigger companies.
Decent quotes and they will compete againts each other for your business. So you can get the rate below 2% ...
Read the small letters: example: is your card machine included. Can you change it for the latest model. Can it handle contactless payments, etc..