Where the race frames not all blank? If it's got a VIN stamp then you should be able to get a V5 you will probably have to register it as a bike though. I am not sure you can register a frame on it's own. My old bike was never registered and I had started the process by getting a certificate of conformity from triumph, you need it MOT'd and insured then it's just a case of sending off the paperwork. The form are available through DVLA ordering system online.
Ok cool so probably the same process as I looked into then as mine was stamped and not registered. You can email Triumph for the certificate of conformity. I posted the address somewhere on here ages ago it should show up in search.
as far as I know you can get a v5 but it costs as the bike was sold for race no vat was paid so aswell as registration fee theres the vat to pay aswell
I have got two triple challege bikes. Both frames have numbers and vin tags ad per normal. I also have got the original form from supplying dealer t3. Will be interested to know jow you get on. Think will have to pay vat and get daytime mot.
Looks like i won't be getting much further tbh as it is just a frame at the moment so no day light MOT It will just stay as my spare frame