Just what I suggested. If the vehicle is not scrapped, exported, SORNed or legally taxed then an offence has been committed by the registered keeper.

This only applies to UK jurisdiction (and there is a geographical limit defined as England, Scotland, Wales and Northern Ireland). Yet I suspect the DVLA will argue that as the vehicle is registered with them, not SORNed and not scrapped its actual physical location is irrelevant. They will probably argue that to avoid prosecution the vehicle must be permanently exported, then re-imported if and when it is to be repatriated to the UK. To the DVLA your vehicle only has five possible status conditions: Scrapped, Exported, SORNed , legally taxed or illegal. It is for this reason that every 12 months I bring the car I keep in France back to the UK for an mot, and I have rescheduled the mot test date to ensure that the RFL is due well within the mot validity so that I can renew the tax disc easily. The car is thus always taxed when I turn up at Portsmouth with a pre-booked mot test the same day. I realise this does not help Tony