Ah, that's your issue then. In my D1 I wired my aux lights to an extra fog light switch and inserted the switch in the blank spot in the same bank that contains the front fog lights and cruise control switches. I have it set up so the aux lights are independent of all other lights. I wanted to be able to use the main beams, the fog lights, and the aux floodlights in any permutation. The tradeoffs are that (1) I now have two identical fog light switches, but I know which is which, and (2) the aux lights will come on no matter what else is happening, so it's easier to drain the battery if you aren't paying attention. Fortunately I only use the aux lights when appropriate (i.e. in the dark on the trail or forest roads), so it is obvious if I haven't turned them off.
Buy a spare front fog switch from Will Tillery or one of the parts vendors here and wire your Hellas to it. I'm assuming your Rover's interior has these features, as you don't list what vehicle this is for. Do a search on the Discovery tech forum, there is a thread within the past year on how to do this. It includes photos.