I still have my doubts thats genuine miles, you only need half a brain cell to see a low miles Omega is worth a lot more than that. So why would someone let one go for such a low price, even with faults?
They are easily clocked, my 140k 3.2, has a better interior than an 60k 3.2 up the road. It is also in far better condition underneath, none of the exhaust heat shields are rusty! In reality, miles mean nothing, my 2.2 goes better with 164k on it, compared to 84k when I bought it 
I'll have to agree with that assessment ..
My 2002 2.2 got it 4 years ago with just over 100k on the clock have spent on it over the years nothing major mainly styling to make it look like an elite and usual maintenance parts and its got a little bit of a rear arch problem starting, fair bit of surface rust underneath, air-con doesn't work never has apart from that its sound...
Now the 2002 "51" 3.2 has 189,000 on the clock, underneath is nowhere near as rusty underneath, steering feels better, engines sweet pulls like a train, gearbox is slinky smooth interior is on par with the 2.2 same with arches if anything better only starting on the 3.2..
Saying that both have had their fair few problems some ongoing hay ho

And I've been to see a lot of Omegas over the years many under a 100k .. An example a "52" 3.2 Elite in black had 65k ish on the clock polish chap owned it

anyways was rusty undrtneath . bodywork Lacquer peeling off roof, bonnet, boot etc. full of scratches, dents, really bubbly arches, interior stank and leather was worn and hard and did I mention it was smelly inside

engine was tappety and full of mayo with blue fumes coming out of the oil cap apparently engine had new gaskets and new timing belt and a full service

was pretty cheap mind £950 odd but someone would have had their hands full with that one.
Same goes for many other low milage cars some looked ok and sounded ok but something was always off with them, High milage ones are not always better but they way I think it must have been pretty well looked after to reach that high milage in the fist place. Did see an ex plod with around 250k on the clock in star sliver a 3.2 auto body work was average and surprisingly arches where spotless few dents here an there interior worn but functional. £800 what put me off was the engine was spewing oil after a Mild/hard test run and being basic.
Knackered now going to bed, take no notice its tired dribble talk