I measured the distance between the centres of the cross tubes today, it is around 67cm, so that makes it an Ami type chassis. Is this the same as aks400?
Today I ran into the most immaculate Pony I have ever seen, it was better than new!
I spoke to the owner who owns a garage and he said he might be able to find me a chassis in good condition. We did not discuss the price though.
I haven't given up on the hope I might fix my chassis though. Given that the middle-rear part of it is excellent and the right not too bad (it might not need cutting at the right after all), I think with some careful work on the left it might turn out great.