From what I read it was "chassis " issues. Or Rot.
I dont think its bad TBH , but I think that they were after a mechanically poor car , but structurally/cosmetically sound car. Its harder to make cash ( or appear to ) if you have a rusty car than a mechanically knackered one.
Ah but Wheeler Dealers isnt about making cash, its about keeping a car on the road and most of the time they make a loss. Anyone remember that TVR that they bought from a TVR dealer? Chassis was so rotten the car was not financially worth fixing hence the dealer wanted to off-load it to some gullible person. However, wheeler dealers bought it, stripped the car down to nut & bolts, fitted whole new chassis, rebuilt it all, then after all that noone wanted to buy it, so they then it back to the same TVR dealer at a huge loss. The dealer must have been killing themselves laughing.
Whilst im chuckling at that memory, some other classic Wheeler Dealer episodes I remember...
Suzuki Jeep - They buy it, and spend a fortune turning it into the ultimate jeep. Jacked up suspension, massive new wheels & tires, CB radio, winch, buckets, harnesses, roll bars etc. Then they take it to its MOT and it fails cos the chasis is so badly rotten its beyond repair. So they sell it to some farmer for a few hundred quid so he can use it to push bales about on his farm.
Porsche 928. They buy one, see it has non original wheels on, so Mike goes to a specialist who happily swaps the mega rare BBS alloys (worth more than the actual porsche) for some bog standard wheels.
Sierra Cosworth. Same sort of thing, Mike swaps the expensive Escort Cossy Wheels & rare RS steering wheel for standard items, plus has to pay the "specialist" extra on top for the cheaper stock items.
Best of all. VW Beetle. Mike buys it as it needs just paint work. Ed strips it down and finds out that all the bodywork is shot, so they then fork out and buy a beach buggy bodyshell for it. When they try to fit this, Ed then finds the chassis is shot so they have to redo all of that. He gets the new body bolted to chasis and then finds out that the engine is shot, so they have to replace the whole engine. So it basically ends up being a completely new car by time they have finished.