Hi and welcome to the forum.
Contact Paul Dawkins via the messaging service on the site. For a small fee he will be able to check the VINs against the DVLA database. If the VIN's show up, then you will have the registration number and you can just apply for the V5 via a standard V62 DVLA form. If the VIN does not show up you will need to get 4 things to get the bikes registered:
1) an MOT for the bike - They will MOT it on the VIN number
2) Insurance, once again they can do this on the VIN number. Contact lee@bikesure on the forum and he should be able to assist
3) a dating certificate - back to Paul Dawkins who can supply these
4) the form to fill in - these are V55/5
That, some fees etc is about it. Latest news is that you can ride the vehicle to the MOT station without a number place providing the frame is insured and the MOT is pre-booked. Check that all is current before you embark.