£325 isn't bad, but ask if that includes the water pump, they're only an extra £30.
£126 is probably because they use the correct VW coolant, not some cheapo stuff from a motorfactors, the G12+ stuff is quite expensive but recommended.
£295, find out what's included in that it might also include brakes, oil, oil filter, air filter, pollen filter etc which for brake parts alone just cost me £60 for the rear discs and pads, still need brake fluid and easibleed kit to DIM, local mechanic said he would charge £150 for rears only inc, parts. Price up the parts then factor in labour, it sounds right. My brother in laws Passat was £395 for his yearly service.