1100GS electrical question

My 1100GS has been laid up in my garage for about 18 months on an Optimate. I did do about 100 miles on it in the Summer last year but nothing else.

I check it every once in a while and all been OK. Dusting it off for the Summer now and today checked all the lights etc. My side and rear light are not coming on, dip and main are fine, checked the fuses all OK.
Put the parking lights on and the front and rear lights came on, so they are working Could it be the light switch on the RHS bar? Or something else?

Just checked again and the lights to the clocks come on when side lights are selected, but no side or tail light is coming on.

Could just be a bit of oxide on the switch contact. Try operating it a few dozen times first off.

All working now after a liberal spraying of contact cleaner to the switchgear and ignition barrel