Thanks guys. Got the thing up on a ramp and had a look. The back is an aftermarket stainless steel box and the hangers probably need modifying to make it fit properly.
However, the classic problem of the real seal corroding has struck and the (OEM) mid section has entirely separated from the joint, it's just resting in place. He sent me away to find a mid-section to replace it with.
I've had a quick look on here and found threads like this: http://www.350z-uk.com/topic/65920-exhaust-bracket-corrosion/.
The only difference is that my backbox is relatively new and stainless steel, so I would only be looking for a mid section. I'd like to keep the cost down as I've just forked out for the car. What's a sensible and cost effective way of sourcing a new mid-section.
FYI - the Y pipe section is OEM and a little scrappy visually, but has some good miles left in it. I'd consider changing that too if it is cost effective, but my priority is to minimise my outlay for now.
Thanks all!