Praise be to whichever deity you mistakenly believe in!!!
Problem solved - airbag light off!!
Well......I borrowed another ECU from Steve Smith (Lanivet) and even though it showed every single fault that Multiecuscan can log, when I cleared them all, all I was left with was the Open Circuit/Short to earth message. Whilst swapping the ECUs I had never noticed the 13mm headed bolt that is in front of the ECU and although covered with the ubiquitous yellow shroud is, in fact, an earth lead. I took the little fooker off and the residue/powder between the terminal and the body would have given the average City Trader a "Semi" - I cleaned everything off, reset the faults - they all disappeared, The ABL has stayed off and after 9 long weeks, my sanity has returned.
OK - I still don't know if it was the earth or the old ECU but WTF.
In celebration I took Katie on a long road trip to Antwerp and then Cologne rather than fly and hire to do some pre-buy inspections for some chunky clients. Katie managed 4.5 hours flat out between Cologne and Munich and didn't miss a beat - who needs balance shafts eh?