I think I finally found the culprit, a misguided attempt to repair a crack in the breather line on top of the left cam cover. I have a new line, but it goes under the intake manifold and throttle body before it comes back in sight. There is an air tight connection under all this I can't see.
Has any one replaced this hose? What needs to come out to gain access?
Once I fix this I think my internship with this car should be over!
Thanks for any advice.
Jack

 

I have a few photos on replacing that line on my page

Link JagRepair.com - Jaguar Repair Information Resource

 

Thanks Gus, hope I only have to change this one hose