deano wrote:
Ok, investigating this as we speak (post/google/thread/whatever)!

CU (understairs) is MCB variety... no split loads with RCD (or
RCBO's: I wish!!)
The system has been extended around the house in many areas so, as
you say... many variables!

Perhaps I do need to call in my pal and get the whole place tested,
corrected and certified then.

Latest: just switched off all the appliances and unplugged them, in
the utility cupboard and the tingling has stopped! Something awry
there then... time to put them back on one at a time and identify the
correlation!

Also... you must be old what's the 'T' and the 'W' of TW&E then?
Can't find it anywhere on t' web

Twin and earth cable.

What earthing have you got at the main incoming fuse? It could be missing or
have a very high impedance.

--
Adam