Importing from Europe

[murf]

I am trying to find out the UK customs/DVLA requirements for bringing a vehicle into England from the Netherlands. The car in question is a 62 Flavia coupe which was brought back to Europe from the USA in 1999. The car has been either in a museum or storage and not registered in Holland since then. The only documentation that the present owner seems to have is confirmation from Dutch Customs that taxes were paid at the time of importation.
My immediate reaction to this news was to perhaps walk away before getting bogged down in sea of official paperwork but then I thought that someone may have encountered a similar situation with their own car and successfully resolved it.
I would appreciate any suggestions as to the  way forward if any.

Murf.