Sorry I really don't know much about this, so take my suggestions with a grain of salt.
I thought that you could easily get some kind of provisional license from the DVLA just by applying and sending in the picture. I think my daughter did this when she was 18 so she could prove her age. You don't actually have to drive but it looks like a license to everyone else.
A few months back we were trying to rent a flat in Bristol and the landlord wouldn't accept the citizen card but I actually think that was them being stupid more than an indicator of wider trends.
HTH!