Dave Liquorice wrote:

The biggest hurdle will be getting elderly relative to admit that
they *may* have a problem and that *perhaps* a visit to the GP and
referral would be a good thing to do.

That's why I mentioned the commercial testers. Quite apart from the
reluctance to admit that there is a problem, many elderly folk have an
extreme dislike for "bothering the doctor unnecessarily": an anonymous visit
to a hearing aid demonstration might be an easier sell.