Mine is a Euro 4 light commercial vehicle.
Euro 4 Light Commercial Vehicles registered new before 31/12/2006 pay the reduced rate of £125 (Was £120 when I first bought it))
But from 01/01/2007 onwards, the government closed the door on this.
So all Euro 3 Navs and Euro 4 Navs registered from 01/01/2007 onwards pay the £185 rate.
Bought mine 29/09/2006 and it was one of the first Euro 4 navs (Dealer gave me a £60 refund on the tax when I went to pick it up from new) Thats the first I knew about the Cheap tax loophole.
So anyone thinking of buying a 3yr old ish Nav' can save a few quid on tax if they buy wisely!
Bob