You don't need one in the uk either, actually technically I don't think you should have one!
Have been investigating this given that most UK registered M3W's I've seen do have a front number plate. Although not an official source
this site suggests you do legally need one, although the reference to kit cars suggest it was written before the M3W appeared on the scene. I quote:
Recent legislation will only allow the sale of 'legal' number plates. It will not be possible to purchase undersized plates in future. Small plates on bikes are illegal. Some owners of modern kit three-wheelers have dispensed with the front plate (as motorcycle combinations do not need one). The legality of this is suspect, as on nearly all “car type” tricycles a front number plate is required by law.The official V796 document tends to support this with:
There are separate provisions for motorcycles and tricycles. Basically motorcycles registered after 1.9.2001 must only display a number plate at the rear of the vehicle. Motorcycles registered before 1.9.2001 can display a number plate at the front but are not required to. Tricycles derived from four wheeled bodies i.e. saloon cars must meet the normal requirements above whereas tricycles derived from motorcycles must meet the requirements for motorcycles.Whilst there is still room for speculation I think the odds are well stacked in favour of it being a legal requirement despite some having got away with it (so far) and even having had their cars pass the MOT test.
