Drawing air at oil filler & noise

[Geo]

I've an S1 with the 2.8 engine, I have a high pitch bearing type noise which I believe is coming from the top part of the engine it's also drawing air in through the vents in the oil filler cap, the draw of air is so high that with the engine running you can hardly pull the cap of, when you do the engine cuts out. If you put a finger over the air vents on the underside of the breather cap the noise increases.
The engine rev's well, oil pressure is high and I don't think its an engine issue, it has a new water pump and a recently fitted alternator.
Any informed opinions or suggestions of what could be causing this and how I sort it out would be gratefully received.
I've had the car for a year or so and when I did briefly use it last year however there was a noise coming from the flywheel, a new clutch had been fitted and the dust cover plate had been bent and was rubbing when the car heat up so I'm not sure if this is a new issue or if the dust cover noise has been masking the other.

[Geo]

It was suggested elsewhere that I check the PCV which I did to find that someone had cut the bottom off it, removed the valve part and left what was a straight through connection. A friend had a spare one which has certainly helped the pressure issue, it's due an Mot so plan is to have these guys set up the fuel side.