On my trip to London last week, I took a cab from Holborn to the City Airport. The meter read 23 pounds when I got there, and I had the cabbie round it up to 25 pounds. That's what I signed the receipt for and that's what the credit card company charged. So I don't know about any surcharge I paid unless he plugged it into the meter before leaving?

He also didn't 'radio' in my card number. I simply signed a sales slip like we used to in the old days before the machine card swipe.