Well after the engineering shop admitted defeat on the seized stub axle in the gearbox this week, glenn picked it up (it's a place local to him) and he managed to carefully cut the dead shaft out with some thin cutting discs, winner. Not bad for a painter
I stripped it today, diff innards are actually OK but the stub axle has welded itself in to the diff casing. Poor design and not enough lube at that point. I guess it over-spun and welded when the shaft on the other side failed. Even with it stripped and on the bench with heat on it I couldn't beat the shaft out. It's propper mullered
Maybe the diff will work again in the future if I find a way of drilling the naff bit out.
I got bored of trying to rescue it so I've built it up with a standard diff for now and got it back in the car thisevening.