Looks like it was perseverance that sorted it for me in the end...heat, pentrant spray - and it seems vice grips hold on much better than spanners, and even those Stillsons - so tough it out ddgonzal I was thinking of giving up a number of times....

I'll have a drink when yours comes out too!

When I get mine out, I will put some of that silver stuff on the threads (anti-seize).

im going to go have a drink

Defintely wont overtighten it! Even put a little grease on the thread to assist in the next time it needs to be undone.

Appreiciate everyone advise on this saga - it was the vice grips in the end that performed better than the stillson wrench.

Dont over tighten it when you put it back in

good work

what a relief

that filler plug was getting the better of us all!

Well looked into the filling through the arse end approach...too hard need a hose with a maximum 5mm OD to get past the ouput shaft.

So had one last go at the bolt with my new secret weapon blowtorch + vicegrips.

VICTORY!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Heated up the housing again, then absolutely leant on the vicegrips with my feet and it cracked! You should have heard the car creaking on the axle stands.....but finally victory is MINE!

Check the pics

I reckon try the arse end approach, let us know if its successful!

You would have to gravity fill it from inside the car with a long hose and a funnel or coke bottle etc.

Go for it!

Worst case I'll just remove the gearbox and take it down to the exhaust guy (who I'm sure has lots of welders...)

Whilst it's in the car it's a bit trickier to go medievil on it's arse...

I'll concerntrate on getting the car wired up and started in the next week - and if everyone shoots down my fill the gearbox from the tailshaft interface....well then I'll have to drop the box.

Have you considered gripping a 4" vice onto that nut and turning the vice with something really big? You could drill your own hole (so to speak) and bog it up later or do what I would probably do... drive the thing into the ground then replace the gearbox.