Rather interestingly my bank (First Direct) in the UK swapped over from a Visa Debit card to a Mastercard recently - I wonder if perhaps there are things going

Rather interestingly my bank (First Direct) in the UK swapped over from a Visa Debit card to a Mastercard recently - I wonder if perhaps there are things going on behind the scenes that consumers are not currently aware of. Rather annoyingly most of my spending with Amazon is on my Visa credit card - can't quite figure out why they are now more expensive to process than the historically expensive AMEX.