So due to me not being able to leave nothing alone today whilst I was at work I thought I'd whip the breather pipe off between the top of the rocker cover and top of the inlet manifold (one with brown and black valve in).
Basically when it was running I could hear a whistling noise (kind of like an air leak) coming from the valve at idle.
So I thought I'd whip it off and pressurise it on the bench at work. Unfortunately whilst removing I broke the brittle solid pipe that goes between.
So I spent this morning looking around work for some pipe I could use to limp me home and after much swearing I came up with this
It's heat shrunk on and zip tied at both ends but it's only got to do 6 miles
Ordered a new one off ads for 28 quid, but to add insult the one way valve was perfectly operational and that noise it generates was just air passing through!