When the gift of membership option is selected on the membership form, the cards/guest pass details page is completely skipped. Please make it so that this page is not skipped for gifts of membership, allowing this information to be entered if available.
As a work around (not ideal) we use the "Special Message" field to gather this information and rename it with JS - look here to see how it looks on our page https://supporting.nms.ac.uk/membership/gift/card. Another alternative is to use the "Comments" field in the same way.