I've saved my credit card details but autofill doesn't work

I use Firefox for Linux on a Lenovo ideacentre desk top and on an Android mobile (Google Pixel). I live in the UK. I've saved my debit card details on both devices and autofill works perfectly on my phone but won't work on the PC. I've checked settings multiple times and everything seems to be properly set. I've just checked (via about:config) that my regions supports autofill and it does. When I try to use autofill, my card details appear in a box but when I click on the card number to fill the details, nothing happens! I've tried disabling the extensions I normally use on the desk top (Privacy Badger and ClearURLs) but that didn't resolve the problem. Any help would be appreciated.