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I do have a wheelchair, but the narrowness of our small London flat precludes its use indoors; I would use it for hospital visits, but since (vulnerable) lockdown, haven't been out since hospital back in February.
Kicking this about today has helped, as I'm homing in on (a) chasing GP who in the past has pushed the problem onto the Orthopaedic hospital (of which more above), and (b) getting a new referral to that Tissue Clinic, who were the best of the bunch.
Of course, it all comes back to the fact that my alcoholism (kicked 18 years ago now) was the primary cause of the amputation, so nobody else to blame for these longer-term problems.
A