middlerhythm Thinking off the top of my head here... but have you thought about doing some detective work i.e. speaking to the mechanics at the garage where the car was serviced and MOT'd? There's just a possibility that the previous owner took the car into the garage to have the whine and juddering diagnosed, and knew full well that a serious and expensive problem existed. Maybe the last MOT picked something up (I'm aware that the state of the clutch and gearbox wouldn't warrant a failure), which the mechanic/MOT tester notified the previous owner about. This obviously wouldn't show up as an advisory, but a record may exist.
Appreciate that this is a long shot, but if the previous owner sold the car to you and was aware of these faults but wasn't transparent in the advert and verbally, then I'd say you've got a case under the Consumer Rights Act as a 'second-hand car bought privately' -
http://www.which.co.uk/consumer-rights/advice/the-second-hand--car-i-bought-has-a-problem-what-are-my-rights. If you can prove that the seller was aware of these faults, didn't declare them in the advert and witheld them from you verbally, and the private sale was through eBay, then I'm pretty sure your purchase would be protected in some shape or form.
Not for a moment am I alleging that the seller was complicit in selling you a vehicle that he/she knew was knackered/dangerous *ahem*. However, I'm a cynic, and unfortunately bar stewards who are that way inclined do exist, and in this situation that would be one of my suspicions.
It may come to nothing, and I may be speaking out of my arse, as some may say that the car was 'bought as seen', but these are certainly avenues I would explore. Good luck.