Is this the right call from the Appeal Court?

[know your limitations]

If the width of the lorry means it has to straddle the white line, there's nothing that the driver can do about it unless he wants to run *off* the road, he simply has no option

He does have an option... he stops. What if an identical sized lorry had been coming the opposite way? Would that lorry be in the wrong for being close to the lines? Would the offending lorry have barrelled ahead regardless then?
Most roads in Britain, even country roads can easily be negotiated whilst staying entirely on the correct side of the road. It justs needs a little something called skill.
If the corner ahead is is tight enough to warrant crossing the lines, your approach speed should be such that you can stop on a dime if required.
I drive a 35 foot, 24 ton rigid lorry and am able to get round what would appear to be "too tight" corners without crossing the lines 99% of the time.
On the rare occasions I do cross over, I give complete priority to ANYTHING coming towards me for the simple reason that I am on their side of the road.
As far as I'm concerned, that motorcyclist could have been as close to the white line as he wanted. I wouldn't ride like that but it's his lane, his choice.
The lorry driver should have read the severity of the bend better.
I noticed it was a foreign driver, so reasonable to assume left hand drive. He was more than likely more concerned with any trees, buildings, branches, signs, etc. whacking his side of the cab, so gave himself a bit of breathing space at the expense of any any poor sod who was coming the other way.
The lorry driver used up all his own space... and more, leaving the poor motorcyclist who'd done nothing wrong, nowhere to go.
A shocking decision by the court.