For Sheffield:
"PPR by telephone or Fax. Radio PPR will not be accepted"
It seems pretty straightforward to me. Time was, you couldn't take an SEP aircraft into Sheffield at all.
If you are really concerned about Sheffield getting your support (which they need by the way) call them , fill in the fax form (dead easy) and arrange to visit them. You only have to send the fax the first time.
It's a great airport, very close to the city centre (not many of those left) and with very friendly ATC and staff.
I'm not a resident.