Ding ding round 1, in the blue corner is DC 15yrs and in the red corner premenstrual DD 12yrs.
Scenario - DD sat at desk in DS bedroom playing game on PC, small alarm clock on desk and time display on PC. DS lay on his bed revising for GCSE exam in same room. DS asks DD the time, DD seems unable to oblige and WW3 erupts (again). FFS 
If they get to the age of 18 and I can kick them out and I maintain my sanity it will be nothing short of a miracle.
Give me wine, lots of it, and a dark room...soundproofed