You are right about the Stealers MOT's, they are not worth a light.
Mine came with a 12month ticket, and the spare wheel was down to the canvas, both front drop links were knackered, and one was not even done up tight. A week after I got it, the rear exhaust section just dropped off, and the drivers side calliper was half seized.
I would hope that private dodgy MOT's are harder to get, so should be a bit more trust worthy.. although after we had paid for the T1, the guy was telling us how he knows a guy who will MOT a car for £50...
Not the guy who did the one on the T1 though... apparently.
You can't beat a bit of knowledge on the car you are going to look at, and a good look round, then at least you can see if anything looks near the limit, and if you still decide to go ahead, use the MOT ticket to give you time to sort out all the problems before the next one is due.
Good Luck Clivvy, hope it's a good un...