Originally Posted by
Geordie405
I agree with
golfmad that this seems a little strange. For example, in the USA there's currently a promotion whereby if you use PayPal in conjunction with your Amex Platinum card then you get up to a $30 per month statement credit. Obviously that's there and the OP's issue is Amex UK but I would doubt there's any blanket prohibition on using your Amex card when it comes to using it in conjunction with PayPal.
There's no problem using Amex with PayPal in the UK either. I do it each month with a 5 figure sum.