All good stuff guys, thanks.
I fiddled about with the INPA software a bit more and got the same error codes as Ooch: 5DF0 and 5DF1, I take on board your comments Clearance diver and as always will go down the easy route first.
So...... on closer inspection, I notice that the left front wheel has a significantly greater amount of brake dust on it than the others. I'm just wondering whether, apart from checking battery voltage first, I shall just change that ABS wheel sensor and see if that does the trick? I really can't see how its connections can get dirty, the blue plastic casing is all intact and when I unplugged it, it all looked pretty clean in there.
I cant work out using the INPA how to check the individual wheel sensors, (first time I've ever used, such stuff). I'm in the DSC menu, which threw up the codes above.