Hi Matt - there is a procedural flow chart on the homepage of this site which takes you to a downloadable form that starts the process. Print the form out and you won't go wrong. You will need photo's and rubbings.
Initially I compiled an explanatory letter including these and then discovered the form. I figured plenty of people have done this before me so I followed the club form form to the letter and included my original letter which I also used to send to HMRC and DVLA. The club library guys were brilliant and I received my dating certificate and an information pack full of advice very shortly after. This enabled me to apply for the NOVA registration and subsequent V5C.
Bear in mind that this is a service run by volunteers, but I thought that the whole process was quick and painless given that I applied to the club early March - got my Certificates back, sent copies to HMRC, received NOVA confirmation and used that to apply for a V5C with DVLA which arrived yesterday. Fantastic service by all concerned. Some of the form filling might seem onerous but I followed the club advice and had no issue's. Remember I did not even realise that my frame was an import at the start of this.