I also believe you bought a poor example, I have had mine for 4 years now (Vitesse sport lux), changed the oil once over 40,000 miles and it is a dream that has been a good work horse too! the only 2 problems I have had have been the electric windows and the normal dashboard peel. AR.
I bought a '93 Rover Vitesse Sport 6 months ago now - and have had nothing but trouble. It's done 136,000 miles, and I've put in a new clutch, new exhaust, new head gasket, timing belt, and new battery.
The windows work when they feel like it. The engine rattles. It's leaking oil. There's no heating fan.
It makes a terrible noise when the ignition is turned on (which is the starter motor).
I paid £500 for it, and reckon I've spent about that on it.. BUT I must say it's the quickest car I've had. It's an 820 turbo, and I won't be buying another one...
Even at this price range you can do better for your money, an Alfa 164, saab 9000, even big peugeots, will generally serve you better and be more fun to drive if you get a good one.
I've had a couple, and have always looked for either low mileage ones, or ones with FSH.
Problem is, these people get them for a couple of grand, teat them badly, thrash them without giving them time to warm up or idle, which is essential for the Rover Turbos as they do not have separate water cooling pumps as does my new Volvo Turbo.
If treated properly, then they are fine. If you ask me, to have lasted over 80 000 miles with the abuse they get is fairly remarkable. Well done Rover. Admittedly the gaskets are crap, but you can find an aftermarket upgrade, which means you can also raise boost - (carefully).
Can't deny that the Saabs/Volvos and others are better for reliability, but the Rovers are fine if you treat them with respect. Sounds like you got yourself a lemon there, son.
Take care anyway.
Just a case of you get what you pay for, buy one as cheap as you can use it, and then strip it for parts. The engine is a great unit for a kit car.. Other than that it is easy to see why they are cheap.