Passport condition
I've the same issue, however, I did ask
at passport control coming back into the
UK a week or two ago..
Short answer was that it was ok even if you can't
see the crest on the front anymore! A few edges
are battered in the way you describe and I was told
that this is fine and expected wear and tear, although
he did say I might want to think about getting it replaced
if flying to the States as they don't like said battered
corners again for the reason you describe.
I've got 18 months to run on mine so I'll just get it done
as soon as I can without losing any entitlement.