i'd suggest not buying it on first viewing, unless you're accompanied by an Omega know it all....

i'm not familiar with 4 pot engines at all, nor that familiar with facelift saloons.... having only bought my first facelift Estate on Saturday (but after having owned several Mini facelift Elite V6 estates)
so my limited experience says, make sure you drive it.... listen for knocking on front and rear suspension.... so make sure you drive it on a NORMAL road, not a billiard table .... knocking and clunking is indicative of needing new bushes, drop links, wishbones, that sort of thing....
drive with window open, and listen .... listen to the brakes, both under proper braking, and when reversing, and in traffic.... clunks , grinding noises, rubbing sounds, are all pointers to needing work....
wobble under gentle to medium braking from 60 down to 40 odd, indicative of either warped discs, or suspension wear....
check EVERY electrical doohdad on the thing.... stuff like cd changer cartridges, , every light bulb, switch and toy.... as well as wipers, lights horn etc....
check oil filler cap for residue, check coolant cap for likewise, and look at the coolant, to check for oil... any oil on the top of the engine is a sign of needing work....
as with the V6, check the documents and service records for Cam belt fitment.... and all other records to get a sense of how well it's been looked after....
some people are fond of 2.2, but for that money, you could as easily pick up a V6.... the difference in real world fuel economy when driven sensibly seems negligible, and the extra toys and smoothness, and potential longevity, are IMHO well worth it....
it's also a bit far from me, and besides i am a LONG way from an expert.... in facelift terms i'm an absolute Noob.