Ok. So here they are:
artonmysleeve
chrisdutton
cryptohubuk
cryptophile-uk
epcdedication
flaybur7
fulcanelli
ijazlikelocals
j-bex
johleen
justinriley
l8bit
magnusbuda
marekvej
mikewilks
ooaldridge
pjhoughton
quintbritish
thomw
zhoudi1220
I ran two queries, because the first came up with someone in Sheffield, New Zealand. So I've added another line that removes New Zealand from the search. There may be other countries with a sheffield too. But with a list of 20 they will be easier to find.
Cheers for doing this for me mate. just checked them all and there is no active users in sheffield, some have not been on for months, some haven't even made a post or comment.
It was great of you to do this for me though. cheers once again :)