Having just replaced the ariel with a high gain job, the analogue picture on 5 is just the same as with the old ariel (fuzzy) via cable it's fine. The ariel is in the loft........any ideas?
I think analogue channel 5's been switched off in some parts of Hampshire and elsewhere - maybe the analogue side of things are just being given up on and signal won't improve, do your neighbours have the same issue?
Perhaps you're best sticking with cable or freeview...
If your aerial is looking at the Hannington transmitter, Channel 5 is broadcast, but at a much lower power level than the other analogue channels. I think the coverage is only designed to go about as far as Basingstoke.