From chili post !!
Just an Update...
Traffords Insurance, underwritten by Lloyds of London have clarified that currently full CAA UK registration is required for the insurance to be valid. Wing only registration is not acceptable by the underwriters, nor is it available from the CAA.
This means that both the wing and power unit have to be registered as a single aircraft, the wing has to carry the registration as well as a fireproof metal plate is required to be affixed to the power unit. Full compliance with the air navigation order and Cap 523.
So we seem to be between a rock and a hard place. The CAA do NOT want us to register with them, but Lloyds of London insist that Full registration is held to obtain their cover. (whether it be from the UK CAA or another EU equivalent CAA)