I can only speak from experience but I once bought a jago jeep complete and running but know log book and I was told there was no chance at all of ever getting to pass a IVA and ended up breaking it. there will be loads of cars not correctly registered but its a can of worms. what is it insured as what it is on the log book say ford escort or a jago kit if you had a bump would they pay out or would your insurance be invalid. My insurance asked is it correctly registered, the mot would not stand on there system it will say its a different car so how can they test it they should refuse it unless he's a mate
don't believe all your told from what I here the IVA is a bugger to get through that's why rebodys are catching on. buying an older kit not correctly registered is a no for me unless you are prepared to go for a IVA