OK, dunnit by credit card following the GBP button: although a Paypal screen comes up in parallel, I don't think it means that you're paying via Paypal. I used to have a Paypal account but then got a lot of scammy emails about "updating your account" so lost faith in it: I couldn't be sure if I was getting genuine emails or spoof/phishing ones!
I was first introduced to Mudcat by the guy who was recording my son and his band: I said something about wanting to get the lyrics of a song I liked, and the guy said "Try Mudcat" - sure enough I got them!
So this must be about 12-13 years ago: thanks Mudcat!