Tricky spot to weld - help!!

Hi,

i need some help on how best to go about this - next to the rear shock top mount there is some rust on the top of the chassie, looks like quite a tricky spot to get to, is it possible to lift the body slightly off the chassie and how difficult is this? got MOT end of June and it wont pass as it is!!!

thanks everyone in advance

how much u want to lift it up while you do it? i wouldnt have thought a small ammount would hurt it...i may be wrong!!!