Further comments having actually read the page:
Membership should be open to non-residents, especially if they have
some connection to the UK (non-resident UK citizen, for example). The
use of proxies means having non-resident members doesn't make it
harder to find a quorum. I also see no reason to restrict it to over
16s. Under 16s can't be on the board, but they can be members as far
as I'm aware (I've read the appropriate Act and didn't see anything in
there about age restrictions on members). I also don't know of a
requirement for a parent's signature, but it probably wouldn't hurt -
the £1 liability probably wouldn't be binding without one, but that's
just a nominal amount anyway.
It should probably be made clear that the register of members will be
made available to anyone with a good reason for asking (that's a legal
requirement, I don't remember the definition of "good reason").
"Guarantor" isn't a class of membership, it's just an adjective we use
to make it clear we're talking about legal membership of the company
rather than being a "supporting member" as v1.0 called it (I think
it's been agreed that we should rename that "friend" if we have a
similar concept to avoid confusion).
I believe holding membership details for 10 years is, indeed, a legal
requirement. I don't know of any requirement to keep hold of the
actual application form, though.
I'm not sure it's a good idea to explicitly restrict the reasons the
board can refuse membership. We already have an appeals process, so
just let the board use their discretion about what is in the best
interests of the charity. It may also be good to add "not disrupt the
charity" to "not bring the charity into disrepute".