Technical rear trailing suspension arm

[tinytim]

brother's 1.9jtd has failed mot on trailing arm bush n/s; intend to replace bush and have removed damper, spring, ARB, brake pipe, ABS sensor, handbrake cable and the large nut on the bolt going through the bush but am unable to remove the bolt, I cannot even turn it despite a rattlegun and a breaker bar; I cannot get at the end of the bolt to hit it out with a lump hammer because the fuel tank is in the way; the bolt "gives"slightly because of the rubber bush and that's probably preventing the rattlegun from shifting it; I might have to drill off the head of the bolt (god forbid) and knock the bolt out from the outside; any advice would be much appreciated......