@Mark it looks like you have two accounts pages, https://singletrackworld.com/account/ and https://singletrackworld.com/my-account/
At first the https://singletrackworld.com/account/ didn’t have any ‘Payment methods’ option. It looked like this:
After emailing you subs department they included the ‘my-account’ link in the automatic reply where I was able to update the payment options.
Then, really strangely, the ‘Payment methods’ option is now available under the ‘account’ link.
Either it’s a bug or I’m going mad. Anyway, I’m letting you know because I would have renewed my subscription two weeks ago if I’d been able to update the payment details more easily.