Cant get bottom shock clamp bolt off my Rover 75

[rumpelstiltskin]

Anyone any tips here.My front suspension spring on my Rover 75 has broken.I'm trying to undo the bolt that clamps the bottom of the shock into the hub.I had it soaking in wd40 over night.I heated things up with a propane torch and it just won't budge and it's getting to that point where the bolt head is rounding.I've hammered on smaller sockets too to no avail.When the bolt head was,ahem,hexagon shaped i had a perfectly fitting socket on it,a breaker bar 'and' a 2 feet piece of tubing for more leverage,just can't break it!!Anyone help?