It may be it wants to see a credit card with your UK address on it. People on this forum state that Apple requires a card from the same country, but nowhere does Apple say that you have to have a payment method from the same country. I go with what Apple actually says. All that Apple says in Change your Apple ID country or region - Apple Support about payment methods when changing country is: "Make sure that you have a payment method for your new country or region." It says "for", not "from". It then refers you to Payment methods that you can use with your Apple ID - Apple Support This may be to simply check if the payment method you used in your old country is also a payment type valid in your new country. Some payment types may be valid in one country but not in others. It does not say anything about your card having to be "from" the same country. This might just be poor wording on Apple's part in its documentation, but until they state clearly that the pay method must also be "from" the same country then I do not assume that it must be.
The only official statement I can find about international payment methods is what Apple says is in its support article: If your payment method is declined in the App Store or iTunes Store - Apple Support : "You might need to ask your financial institution to allow international purchases on your debit or credit card". If anything this is supporting the possible use of payment methods from other countries.
Apple has it designed so that you should only change country settings if you have indeed permanently moved to a different country. Since Apple does not specify what the exact requirements are for international card use, the easiest way to ensure you do not have problems with your payment method is to use one from the same country to which you account is set.