[maitology]

I mean...it's an exhaust leak isn't it. If the exhaust gases were exiting via the tailpipe you wouldn't smell anything at all. So some aren't, they're exiting in the engine bay somewhere, exclusively under higher pressure when the engine is stressed and then you're breathing in cancer while in the cabin. Get a recording carbon monoxide and particulate detector, get some data and put it to JLR. And then report it to your local consumer safety agency.

 

[maitology]

Ok...couple things
1. Are you smelling exhaust (smoke) or fuel? If it's fuel the air/fuel mixture may be rich and be dumping raw petrol into the manifold.
2. If it's exhaust (smoke) you're smelling, it is accompanied by an unusual sound like abnormal rumbling or rattling?