2001 Vauxhall Zafira egr valve

Hi, I have just experienced this problem only worse!!
Last year the engine light came on and eventually my garage cleaned the EGR valve and all was OK. A motoring holiday in France sorted out the problem fine. Principally, I do short hop journeys and rarely the motorway. Last week I bought a genuine Vauxhall EGR valve off of Ebay and arranged to have it fixed on Monday and kept it in the car ready. On saturday, I got about 2 miles from home and the car ground to a halt. AA arrived and to my surprise he replaced the EGR valve in about 20 mins. How much will a dealer charge for that sort of service?? Drove away, fault light came on and into limp mode again. AA man followed me home at about 20mph and suggested that the fault was now with a blocked exhaust from the hissing sound it was making. I limped it into another garage on Monday (they do commercials mainly) and yesterday I picked up my 'new' car. The garage I got it into, not my usual one have dealt with problems like this for a number of years and knew exactly how to handle it. They took the exhaust off, soaked it in 'TruckWash' and then put a hose with clean water to thoroughly flush it out. Initially, it was blocked so badly the water would not run through but after a couple of hours was clear. They reckon they have cleared about 80% of the *rap that was in there and by better driving, like 'taking of from the lights' to heat the exhaust all helps. The mechanic also swears by BP Ultimate as supermarket fuels are more full of sulphur and eventually the cost and mpg will be evened out by buying a more expensive fuel, even if you don't get your Clubcard Points!! A little bit of a thrash up the motorway will help too. They put an additive into the tank as well that attached itself to the remaining bits of carbon that reduces the temperature at which the exhaust will burn it off. The cost of the cleaning, £160. New exhaust from Vauxhall, £1300ish. No brainer really. I learned a lot from this episode and I now know what to do. Blanking the EGR off makes no sense and may cause more problems in the future. I said to the AA man. "Fed up with diesels, will buy a petrol car next time." His reply was, "We have as many problems with their EGR valves too!" Hopefully, someone will find this useful.