Until recently the UK solutions for simple card acceptance have been decidedly second rate. As most of them don't accept chip and PIN, you can't use them with VISA. But now I've signed up for WorldPay Zinc which does all the main cards (except American Express), and so far I'm very impressed.
You can take cards over the phone via their website, and you can take cards on the spot using a little chip and PIN device that links to your smartphone by Bluetooth. There's a fee of £59.99 to buy the reader (but see below for a discount), but apart from that, all you pay is 2.75% of the transaction - there is no flat fee as with Paypal, and there is no monthly subscription.
They have a promotion on at the moment if you use this link to go to the WorldPay Zinc site and/or type in this promotional code: FR497816 when registering you will get £20 off the WorldPay Zinc keypad. (And I get a reward too.) Which can't be bad.
So far, very pleased with it.