[Audidothat]

An update....

I'd stripped the car down as described in Delboys guide already and today found a small tear in the hose underneath the shrouding, which I had to pull back to access.

I took a different approach. I assured myself that I had found the culprit section and cut the hose 1 inch above the tear. I had bought a section of hydraulic hose already, cut it to length and joined it to the existing hose.

Re-assembled using jubilee clips, filled and bled the system, the grinding & noises slowly reduced and all seems fine. It was a right pain taking the airbox apart again just to check the level after a drive around town, really annoying isn't it!

I'll keep an eye on it and hope my repair works. Oh and I need to buy lots more screws to better reattach the wheel arch liner.

Thanks all for the assistance.