📝 Pay+ - Would a refund processed succeed if the associated card had now expired?

(Response from Barclaycard)

The card issuer should be able to link the refund to the new card as long as the account hasn’t been closed.

It should be noted though that although this will be the case in most instances there is not a regulated position that this is the process and refunds could still get rejected by the card issuer if the details are different.