Falcona4

Hi, my local DCC installer is having some trouble getting my new Dapol O gauge class 08 shunting lights to work at the front of the loco. Sound, top headlights and rear lights are working fine. To the rear of the motherboard there are two plugs connecting to both lower and upper lights, which work fine. On the front there is only one plug connecting to the upper light, which works and we can see the lower front lights wired up as well, but we cannot seem to turn them on. Has anyone encountered this problem? On the instructions FO is listed for directional headlights, which do work. No joy from asking Dapol so far....is it perhaps something on the Dapol motherboard.