From the HTA.
21. (1) Subject to subsection (2), number plates for a motor vehicle shall
be attached to the rear thereof.
(2) The number plate issued for a truck-tractor shall be attached to the
front thereof.
(3) Every number plate shall at all times be securely fastened in a
horizontal position to the vehicle for which it is issued so as to prevent
the plate from swinging and at a height of not less than 300 mm from the
ground measuring from the bottom of such plate, in a place and position
clearly visible and legible and shall be maintained free from foreign
materials.
9 times out of 10 you may get away with it, but you CAN be ticketed for it.
Science will fly you to the moon, religion will fly you into buildings.