Section 33 of the Principal Act is amended by inserting after subsection (3A) (inserted by section 21 of the Act of 1968) the following:

"(3B) An issuing authority shall not carry out nor cause to be carried out a test for a certificate of competency unless the mechanically propelled vehicle in which the test is to be carried out displays on its front windscreen

(a) a licence taken out under section 1 of the Finance (Excise Duties) (Vehicles) Act 1952, or

(b) where the vehicle is a vehicle to which section 18 applies, a test certificate,

for the time being in force, in respect of the vehicle.

(3C) If a licence or test certificate referred to in subsection (3B) is not displayed in accordance with that subsection, the application for a certificate of competency is refused and any fee paid in respect of the application is forfeited.".