VAG dealers are routinely charging customers between £600 and £1300 to replace EGRs. Quite a lot of dismantling is involved to remove the old one and fit the new one. But £1600 is ridiculous. If this is a 1.6TDI, subject to the impending NOx emissions defeat software and hardware fix, and you bought it from the same dealer who wants £1600 to fix it, tell him that because he originally sold you a car with illegal emissions, you regard the EGR clogging as a symptom of that and you want the work carried out free or charge or you will take small claims action against him. Otherwise find an independent specialist to do it.