All sorted, the mityvac tool I ordered from fleebay arrived a day earlier I wasn't expecting much as it only cost £14 including postage but it worked well and enabled me to found my fault within 20 minutes.
I attached the vacuum gauge to the EGR valve pipe to ensure the new valve which the car salesman had fitted was not leaking, EGR valve good. I then attached it to the EGR vac solenoid, that too was OK. I then attach the mityvac to the pipe going to the valve haha no vacuum, getting somewhere.
I could hear what can only be described as a farting noise coming from the little unit (which looks like a PRV or one way valve) at the bottom of the vac solenoid on the left side of the radiator. By removing the PRV and blocking the pipe with a bolt I then had vacuum though it dropped off within a matter of seconds. At this point I started the engine to ensure the vacuum pump was working OK, and the gauge needle what jiggling around like a jumping bean on a beating drum.
I checked the pipe leading from the solenoid to another solenoid near the fuel filter and whalaaaa that pesky 3mm plastic pipe had been rubbing on the air box and had three small pinholes in it
. Made a temporary repair with good old duck tape (until I can acquire some pipe from work tomorrow) started the engine and had a nice stable vacuum of -480mmHg. Put all valve and pipes back together road tested and alls good no Engine Management Lamp,no loss of power and it's pulling like a train.
Happy happy happy
Omega Owner here now!!!
Thanks for all the pointers though guys much appreciated.