Hello Randal, I don't know exactly what a travel card is but, as with qualifying Bus Passes and Blue Badges, might it be possible to contact the issuing authority and have a conversation with them? Although I have no firsthand experience of this, perhaps you could approach your local council or department responsible for renewals and ask them? I'm sure this must be something they have been coming across more frequently due to COVID and the benefit backlogs. I know that Blue Badge Holders have had some success by producing their letters/documents of benefit renewal as supporting evidence. It would do no harm to try and make contact, but I suppose bear in mind that different authorities may well adopt a local policy for this situation. Good luck.
Nothing on this board constitutes legal advice - always consult a professional about specific problems