If the police had a little common sense they would create an online system for renewals with a fully populated form including what you hold, can hold, criminal record, medical declaration...
All you would have to do is confirm the details, apply for additions and removals, approve a binding document and give permission for your medical record to be probed.
New applications wouldn't need to be overly difficult too.
Most people I know can shop on amazon, firearms licencing doesn't need to be anymore complicated. Both end up with a legally binding contract and the supplier knowing more about you than you do .
I don't think the issue is whether or not old people can do online firearms licence applications/renewals, it's not easy for for the most IT literate person. The issue is the apparently deliberately difficult process.