After hearing a screaming noise coming from under the bonnet this morning on the way to work, when backing off boost - I sort of self diagnosed a failed PCV valve being the issue!
Was still on the one it came out of the factory with!
So I went online and found a replacement from GSF for £25 - result in my book!
Finished work early, collected the new valve and have just installed it - one of the easiest jobs I have done!
Some pics for those who may attempt the job in the future
New valve straight out of the package!
Old one that was screaming to be replaced!
4 screws later and it was off
New one installed and good to go
No more screaming!