I always seem to get a petrol like smell around the rear. No obvious leaks and the fuel tank remains pressurised. Any ideas?

Check the rubber seal on the top of the fuel pump carrier for cracks.

tank cap seal?

I replaced the cap seal. No difference. It holds pressure also.

Kelv. Where is this exactly thanks?

Not Kelv but I don't think he will mind.

Lift boot carpet, back right in boot floor there is a round black plastic cover secured by 3 (iirc) small screws, remove this cover which exposes access to the fuel pump. You can then inspect the seal that Kelv refers to.

Fuel filter? Above plastic cover that is just Infront of driver side rear wheel

The fuel supply line stays pressurized when engine off by non return valve in pump all the way through to the injectors. You can rule out fuel line leaks from pump hose connection through filter and all the way to injectors (unless your injectors are leaking) by difficult warm starting after a long run - a reduction in fuel line pressure causes the petrol to vaporize in the lines under the bonnet when hot. Unless you have this problem, my money is on Kelvs suggestion.

Thanks for filling in for me Clanger

Kevin, the rubber seal is as seen in this picture.. the black ring at the top..
Pic

Thanks guys. Took the panel off and there is definitely a whiff around the fuel pump so that look like the issue. No obvious leaks but probably the issue then. Will get a new seal before I dismantle! Is it easy to change. I assume just unplug everything, unscrew the top and stretch it over?

Kevin, have a close look at the plastic unions on top of the fuelpump assembly - the pastic gets brittle with age and there have been several cases of these cracking or even shearing when disconnecting the lines

OK. Had a look but nothing obvious. I could take the pipes off but may cause more damage. To be honest I don't thing I will bother fixing it as it isnt too bad. No signs of fluid and it seems you need a special tool to get the top ring off? If it was a simple fix I would do it.

It just unscrews, shouldn't be any tighter than hand-tight. You might be able to readjust the rubber ring for a better seal.

It is certainly a job you can undertake yourself..just be careful when disconnecting the hoses from the nozzle and avoid excessive force. As Edinburgh mentioned, they can be brittle.

If you are struggling to release the locking ring by hand as mentioned by Rob40, then you could use a large flat bladed screwdriver and hammer to ‘chisel’ the ring loose. Wrap the tip of the screwdriver with a piece of cloth to avoid knicking the plastic ring.

Finally sorted this. It turns out it was just the plastic fuel can that I store in my garage quite close to the filler side of the car...Doh!. Plastic fuel cans always smell of petrol I find as some must be escaping through the walls. All sorted now - changed it to a metal one!

That has to rank as the most labour-intensive non-fix ever undertaken on a coupé

This should have a "How to", 1st dismantle the whole car, reassemble, then move the petrol can next to the car, buy new petrol can.