After the valves age, they can either fail or become noisy in operation (similar to a diesel), Vauxhall sell replacement valves for a fair price, something around £170, HOWEVER, you can overcome a faulty valve by simply blocking the exhaust gas route through it.
Doing this should not cause the car to fail its MOT on emissions, and it will not affect the running of the car (as long as the electrical plugs remain connected)
Anyway, here is a simple guide to carry out this procedure...
**SOAK THE BOLTS TO BE REMOVED WITH A PENETRATING FLUID BEFOREHAND TO AID REMOVAL**
Firstly - Located your EGR Valve - It is the small Square valve unit, mounted directly next to the DISPack
Now, Remove the Plug Connector and the small pipe that goes to the Inlet Manifold
Then, using a T40 Torx Drive, unscrew the 2 bolts securing the EGR Valve to the engine, remove the Valve, which should look like this;
Next remove the original Gasket (made from sheet metal) KEEP THIS SAFE AND UNDAMAGED!!
Clean the mating faces of the EGR Valve and the Mounting location, something like Wet & Dry paper is good, or, as i did, Scotchbrite is also good.
Now, find some Gasket Material (you could use tin, from a drinks can, or sheet steel or proper gasket material as i did) - Mark around the original gasket, adding approx 1mm to the outer edge, also mark the 2 mounting holes!
Cut the gasket to shape - you may need a grown up to help... haha - below is a comparison of the original and my freshly made gasket
Then, refit the whole assembly - only use your new gasket, not the original, then bolt back in position, and reconnect the vacuum line and the electrical plug
All should look well, and like this
Now, start the Engine, making sure the Engine Management Fault light doesnt come on, and then give the car a quick run before checking for any signs of gas leakage.
If the EML Does illuminate, check the electrical connection to the Valve...
Then, its Job Done, time to get down the Pub...
DISCLAIMER - I hold no responsibilty for any problems this may cause to the running of your car, this is for reference only. Also, if an MOT failure is caused by emissions, i hold no responsibilty. You carried out the changes, and it is easily swapped back to standard if needs must