On very random mornings (say 3 mornings a week), the RR will start fine, run fine etc, but when I start to accelerate up a hill about 500metres into the journey, it'll puff out some grey smoke and I end up with loads of error messages on the dash and it'll go into limp mode. I restart the car and continue the journey and everything is fine. It is also fine when I start the return journey some 10 hours later with no issues whatsoever.

It's recently had new BAS silicone top intercooler hoses, as one was split, which was causing a similar error. It's also just had a major service.

I did notice after the service that there was an oil leak (could smell oil burning). The oil was dripping on the first exhaust silencer on the O/S. It was returned to the garage, who said it was the rocker cover gasket and was replaced. I had a look under the car again yesterday and there is still a noticeable drip. The car is booked in again next week, but I want to go in at least half prepared as to what it could potentially be. Sorry for being so vague, but any ideas?

It's a 2010 (facelift) 3.6tdv8.

inlet manifold??

a smoke test should reveal this.