Yes I do now believe in fact that my engine required the top end overhaul because of lack of use during its 12 years so that seems sensible to have inspections but it doesnt seem sensible to get the work done and then the engine is still expiring after 12 years plus 20%.
I dont believe there are great benefits to having it in the name of a company and it seems it is correct that if I rent it to myself then I wont be able to once the 20% expires as that will be public use. It looks like I will either have to get a new engine by then or pay the VAT and make it purely for private use which is probably the option I will choose. That will cost loads of course to pay the VAT £27650 but then I wont need to charge myself VAT in the future.