To keep things simpler, I'm looking at Spanish-registered vehicles.
Are there any special restrictions on vehicles on the island? Any gotchas that I should watch out for?
One old van I'm looking at is registered with a number plate starting MA (for Marbella) then a number - which I gather from Wikipedia is the old numbering system used in Spain. Would that need to be re-registered with a plate starting IB to be kept in Menorca? Are there any issues with buying a car on the mainland and moving it to Menorca - is it as simple as taking it on a ferry?
I would be grateful for any tips and experience you have on this. Thanks!

John