I didn't bother claiming a PPI refund from the Monument card I used to have as
(a) I didn't regard the PPI as being 'missold' ; and
(b) I didn't think the sum would amount to much anyway.
When I got a letter from the firm who'd taken over Monument, inviting me to apply for a refund, I ignored it for ages as I thought that it was probably just yet another bit of PPI spam. However many months later, I decided to look at the website mentioned in the letter. To access it I had to enter the code given in the letter but that's as far as I intended to go. (i.e. I still didn't intend to claim). However as soon I'd entered the code I saw a message saying "Thank you for your claim, which is now being processed". A few weeks later I received a cheque for £3000 ;-)