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