I have only tried it on an a-series and when I tried it it was possible to do without moving the rear subframe, but a lot easier when lowering the subframe 5cm or so. that way you dont need to undo any of the pipes and stuff, just undo the two front mounts and support it with a jack or something.
I've done it on my r100, just disconnect everything exhaust needs to come off as it just makes life easier. Undo the mounting bolts and as dot matrix says just support with a Jack or another person and wiggle it out.
N447AKU Kingfisher Blue R116 Kensington (SCRAP)
M356NVP Flame Red R114 Gta (WRITE OFF)
M752PDB Kingfisher Blue R111 Kensington SE (CURRENT PROJECT)
the filler neck clips can be very rusty, its worth spraying them with lubricant a day before you start.
I find it easier to lower the subframe slightly as this avoids damaging any paint as its extremely tight space.
the hand brake cable is also clipped to the tank.