can anyone attempt to answer last bit of post

im still struggling with this andy i have the double operating as i
want i.e left hand switch switches wall lights on and off and right
hand main lights on and off however the main switch wont switch
anything unless i switch the main lights off on the double switch and
then the single switch lets me turn the wall light on and off all
right except for the last bit which requires main switch to off/on the
main light not the wall light. ps is it safe to leave like this
overnight in your opinion?