On UK bikes, switch o-1-2-3 controlled strobes and siren. o was off, 1 was front blues, 2 added siren, 3 was a non-locking (momentary) position for "yelp". 4 and 5 were rear blues pole and rear reds. They varied slightly as forces rearranged the occasional function to their preference.
There were two types; one had controls for the sidelights and headlights as Uncle Phil illustrates, and one used that switch for alternative functions (the lighting being assigned to the ignition wiring).
If your switch marked o-6-7 has no effect on your lights, you have an extra couple of choices in your wiring.
The wiring from the switchgear ends in a red and a green connector, plus a single bullet connector. The red is for ignition and lighting; green and bullet for the optional connections.
Simple diagram of the wiring for switches 1-5 is below.
Whether there's any continuation beyond the switch-side half of the green connector will depend entirely on whoever decommissioned the bike.