Looks like a 2B sliding pillar:
https://nw.rhocar.org/identification.htm
No 2B is any more difficult to get through IVA than another. Plenty of people have done in and some pass first time so although unlikely, it is possible. Commonest fail points are probably sharp edges, emissions and failure to interpret the regulations correctly.
Buying a registered car is the easiest option but then you don't have the satisfaction of doing it yourself. Part built kits can be more difficult to register if you're not careful with the paperwork, you need to prove that you've done most of the work, ideally with receipts and photographic evidence.