I have to agree with Cpt Scarlet in that the earlier models were not particularly well built and they also suffered from many problems, I'm not sure TVR even knew what the word safety meant. But the later models improved on build quality a lot but at the same time you have to think for such beautiful and uncomplicated cars there must of have been a reason why they went bankrupt so many times?
I also think you are possibly attaching too much value to the restoration and I would seriously question just why a car that is claimed to have only covered 10,500 miles in 24 years would need all that engine work something seems a little off with that. I would ask to see the old MOT's which would confirm the mileage, The replacement of the smaller perishable parts such as the pipe work and rubber items due to age I can fully understand and they are not that expensive but the engine rebuild would concern me. Although no price is listed for this car looking at the others for sale and sold he seems to have very high prices, I'm not sure about the cost of shipping and import costs but find it hard to believe it results in the price doubling which is what he seems to ask from what a car in the UK would cost.
Finally I do understand the heart wants what the heart wants but from bitter experience would suggest trying to find out all you can first as I have said something just feels a bit off about this car to me. But good luck with whatever you decide.
Marc