When I had my NatWest Mastercard stolen, NatWest issued me a new card with a new number. If I need to renew any annual subscriptions, I have to now telephone them with my new number. If they try to use the old number, what would happen? Obvious I am sure, just wanted to double check. Easier than getting through to NatWest on the phone !!
The answer is not at all obvious though - maybe persisting on the phone with Natwest is best to find out what they actually do.
They can either decline the transaction or accept it and pass it on to your new card. Obvious.
I have had transactions on an old card passed on to the new one - although in this case the old one wasn't stolen, just changed for a new one with the same issuer with better benefits and a new number.