Apple Pay not working with TFL

I have checked with my bank to see if it's an issue their end; registered the card again with Transport for London (TFL); deleted and re-installed the card - it never works.

It works fine literally everywhere else - all retail shops/apps etc. Now whenever I travel on public transport, I have to take my phone and my card together (which I don't really want to do) because Apple Pay is denied on all buses so I have to use my physical bank card. This has only been happening since end of August and was never an issue before.

I have an iPhone 11 on iOS 18.6.2.

Any help much appreciated.