Thanks to "Randombloke", "Old'uns"and "Ronin" for advice. Problem solved. It was wrong to assume that both bulbs wouldn't blow at the same time. I now know where that second fuse box is and all fuses were intact. I located the relays and could here them clicking when the switch was thrown, so it was into the back of the light cluster to check out the bulbs. Sure enough they had both blown. Cheers