What Kevin said, but I didn't have any documentation for the NOVA, just the number. They did miss it the first time (despite me putting a fecking great ring around the number with a red felt tip) and sent the forms back anyway, though. I rang the HMRC number they provided me with who advised me, on checking the number that:
(a) The duty on the bike was 'secured', ie paid up.
(b) DVLA were a bit thick.