I suspect
some bovine excrement
MOT 29 nov @ 76,401 miles car serviced .
A "service" at most back street garages is normally and oil and oil filter change. A "service" at a main dealer with a Vauxhall badge out the front is often a pretty checklist suggesting how they can extract more money, plus if you are lucky, and oil change. If you are really lucky, maybe an oil filter change, although I've never had the pleasure of them changing the filter...
from service history book stamped / ticked boxes (all the same local garage)rest of history main dealer

9th service (2013 @ 71,5k)
plugs, air,fuel filter,brake & trans fluid oil/filter change
10th service (2015 @ 72k)
plugs again ! fuel filter again ! oil/filter change
11th service (2016 @75k) brake and trans fluid again

oil/filter change
12th service (2017 @76401 is not in book but invoice for the brake pads 2 sets , discs front and rear, ,oil and filter,air filter,spark
plugs ,2 goodyear tyres, bulbs ,MOT
that last service was more than i paid for the car
i know they did disc and pads all round and tyres,oil looks clean(dunno about filter so i need to do an oil & filter change ,got them) air filter is clean,
I very much doubt ,even if the engine had spent 5 months at the bottom of the north sea ,there would be as much aluminium
rust that came out when i pulled 2,4,6 coil pack had they pulled it (to do plugs ) nov last year ,
I brought the omega late march ,started using it mid may .
am I paranoid ,or did the garage have the OAP previous owners pants down , probably more than once .
