Cheers guys, I lifted but yeah it was a tight fit and got scared of bending something I shouldn't in case I'd missed something needing removing! I discovered old brake line tucked up there to in situ and the new brake lines previously fitted seem to have just been stuck on as a bit of an after thought not in original placing.
Gutted that 2 studs broke off... One right at the base and the other part way down... looking back I should have maybe re cut the end of the thread that caused the breaking of the 2nd stud in the end.
Now I guess it's a case of seeing how many clips I break removing that trim panel!
Packed up earlier for a short while as going to look at a van shortly. But the tank is hanging still in place till I get that seat out. I think I'll go and clear the car out again and see if I can lift it out!