john jacob jingleheimer schmidt. my fucking nemesis. the bane of my life every single day. his name is my name too
as someone with a near but not completely unique legal name (at least in terms of first/last and being in the UK), yeah, you'd be amazed at the number of admin headaches it can cause
go to bank to get old account shut down
present documentation with our full name, our account number, our card, specifically tell them "if it comes up with this middle name, that's the other one"
and they still pulled up the other person's details and would have potentially given us the cash in their accounts had we not told them to forget about it
(looking back, the bank got lucky this was pre-GDPR)

