Does it actually smell strongly of petrol though?
I had a similar problem with my car at one point, ...I put it down to the De-Cats at first but as it persisted I investigated it further. Turned out I had a fuel leak in my engine bay coming from the FPR (fuel pressure regulator) which was dangerously dropping fuel onto the exhaust pipes/manifolds below.
I fixed it by having a new pipe made for the FPR as the old one had developed a hairline crack which was the cause of the fuel leak. Very dangerous but luckily I found the leak.
It's smells more like strong burnt fumes
But I will investige that one cheers