So my understanding is that the schedule is Oil Service / Inspection 1 / Oil Service / Inspection 2 or ~ £150 / £550 / £150 / £900 with service every 12-15k or 2 years? Would depend on where the car is in the service schedule but even a Inspection 2 at £900 isn't too bad if it lasts me 2 years.
As mrk says, decent Indy's are usually the first thing to find, looking at receipts £120 for the oil service, and £600 for the Insp 2. Fox is right, some Indy's are cheaping out by not doing certain things, but a good specialist will just offer better VFM.
In terms of things to check,
1. Brakes - these are relatively expensive, so look at disc condition / pad condition if you dont want an immediate £500+ bill for a pair of discs/pads
2. Suspension items - there are many bushes/joints that wear, so it is good if you can get it on ramps to get it inspected, nothing is that expensive, but it can add up, looking at my receipts, it's quite eye-watering.
3. Clutch/DMF - these last around 100K miles, but can suffer from having a hard life, the DMF might be a bit grumbly, and it's around £800 for a clutch/dmf change
4. Paintwork - Front Wings/ Rear Arches often go, I'd probably prefer something already sorted unless my intention was to get it done to my own standards, then I'd want something unmolested.
5.General sensors etc - there are lots of things like MAFs/Coil Packs/Plugs/TPS/Lambda sensors that can go, nothing too wallet busting, but again they start showing signs of deterioration around 80k miles.
6. Vanos - can be largely rebuilt etc, but as long as no EML, and it runs well/pulls strong doesn't overly have massive hesitations all the time, it's probably OK
7. SMG - Bit of a minefield, the pumps go quite often, and new ones are prohibitiively expensive now, but there are a few refurb options that people tend to try first, If getting SMG, get it hot and abuse it a little, try to really give it a good workout, a few people tend to sell at the first yellow cog of doom lights, so stressing a little will at least help determine if it's borderline.
Other than that, just the usual car things..
If your aim is to buy something passable with a little bit of wear to items, and only do a few miles selling it on with only slightly more wear, you might be able to run it cheaply..
My problem (and I suspect a lot on here), you start refreshing things since it feels quite a 'special' car, and whilst I love doing this, it's not 'cheap'..