2

In sub-paragraph (1) above “agricultural engine” means a vehicle which—

a

is designed and constructed primarily for use otherwise than on roads,

b

is designed, and used, solely for purposes relating to agriculture, horticulture or forestry,

c

is used on public roads only for proceeding to and from the place where it is to be or has been used for those purposes, and

d

when so proceeding does not carry any load except such as is necessary for its propulsion or for the operation of any machinery built-in or permanently attached to the vehicle.