My dads is the same though, fairly at the top (he has the same car pretty much) and he has done at least 15,000 miles in it like that. I will have a play tomorrow and see exactly where the biting point is.
At least now its running if I decided to ditch it then its worth something, but then I see its not using any oil, there is no smoke at all at idle there is quite a lot of good stuff about it. So its if a new clutch, new rollbar bush and eventualy brake pipes will cost more than a new car which will also have issues.
The bottom line is the chasis, I am pretty sure the engine will last, I need to take some more pics from underneath but this whaty I have so far.



Now if the chasis will last another year or so the repairs are worth it, but if the chasis won't even last till Mot in May then its not.