The hard U is a Liverpool usage - the Irish favour 'fecking' (also used in Liverpool due to the high Irish influence
The toffs us 'fawking' because they think it makes them sound superior
I never heard 'Facking' - north of south of the Thames - a dyslexic form of mining, maybe?
They don't know what the word means in Wales - they don't go in for that sort of thing since The Chapel took over!
Jim