Removing all the VIN plates is a bit of a double edged sword. You want to keep the registration document live with the car sorned but if it goes to a scrapyard they may signal the DVLA that the car with that VIN number has been scrapped and then you have issues at registration. With my first kit build I stripped an MX5, removed all Vin numbers and scrapped the shel and got an age related plate. With the next, a Focus ST170, did the same and the scrapyard were very iffy about taking the shell as they thought it may be a stolen stripped car. Took a while but got it sorted, no age related with that one as you can't use enough bits from it to qualify.
If you search on this forum there is a very good guide, by Stot I think, which details all the forms required and how to fill them in. Be aware that the things needed for IVA are different than they require for registration. I can't remember the forms numbers but they were something like V55/5 and V4
See this link