Front discs, pads & callipers. (Partially Seized and have slightly warped discs, pads are separating)
Rear discs, pads & callipers. (Partially Seized and have slightly warped discs, pads are separating)
ABS sensors at front. (Speedo stopped working a week after I purchased car.)
Alternator. ( Has failed and needs replaced, confirmed by RAC breakdown who recovered me. )
Cam Shaft Variator. ( Sound like a diesel on startup - Not for Mot but required )
Cam Belt + ancillaries. ( Was last changed at 71K car now has 99K - Not really needed, but in for a penny in for a pound)
Hand brake cables. ( Stretched )
2 Flexi hoses. ( ALmost worn through )
Exhaust manifold. ( Blowing from underside, was not blowing when purchased )
Air Bag warning light permanently on ( Was not on when car was purchased )
Floorpan welding work in at least 4 places ( Was not checked - my own fault )
I think from memory the air bag like won't reset when it's found a fault no matter how minor, so plug in the diagnostics, and it should be simple to reset. GTVs are renowned for tripping this when you move the seat!! but it could be related to the alternator going.
Needing to overhaul the brakes on a cheap car, is no real surprise and lets face it you'd rather know they were right.
The cambelt and variator can't really blame the seller, they aren't due, but I don't blame you for doing them, better to know they are done and up to date.
Assuming the alternator lasted more than a couple of days, I think that is probably just plain unlucky, the seller could have charged the battery so that you didn't know but that won't have lasted long, especially if you used headlights\wipers etc.
Floorplan, well that's a *****, the seller may or may not have known, I made the same mistake, and I personally don't think the seller knew in my case, but like you say you didn't check, I didn't check either, I didn't fancy crawling under a car when it's muddy etc, but I wish I had, we all live and learn.