Hi not you know what, if it is what you're saying your drinking and how often, no more and you know it doesn't rule your life (eg if you wanted to go for a run or a friend suggested a coffee, you wouldn't feel like you were missing out), then you know yourself best. Changing my tune a bit (!) but it was what you said about not drinking when stressed or having had a bad day, unlike the past. That's really important and it's good you have that self awareness and control.
With the school thing, I didn't want to scare you but I'm relieved you're taking it seriously. There is no threshold, one teacher for eg could refuse just on the basis that she smelt wine, even if no ill effects. Not banging on, but with the recent safeguarding tragedies everyone is on high alert. If you cut down to only 1 on a school day it would be un-decetable, or keep for weekends or school hols etc. I know your kids are rarely off but sod's law and all that.
Serious question though, why don't you just not drink at social engagements? Especially if you don't enjoy it. I'm a bit like that now. I much prefer the odd fruity gin and lemonade at home than out, unless at a nice cocktail bar. In standard pubs the options aren't as nice, you've got rounds and it's a bit of a trial. I do have one or two but tend to have no more than that.
One thing I found a while ago was drinking gin three/four times a night. Never over my units, and it did taste nice - but it was for the bizz and while it was harmless I also knew it was at risk of becoming a habit. So now I have a nice gin glass, topped with ice and filled with either belvoir elderflower presse or the tesco citrusy adult soft drinks. Still a 'treat' but less habit forming. Logistically speaking - if I drank 1 gin three times a week to relax, after a while I would get used to the effects of that gin and it would become two.
I hate late nights too, clubbing is the worst. I'm quite often in a cocktail bar in the afternoon - shopping, lunch, 1 or 2 cocktails, usually getting some me time. By quite often, maybe twice a month I do that. Like I said provided you feel in control and happy that's what matters. Do keep an eye on things, especially at times when things get stressy, and be honest to yourself. Be careful about the school thing too.
Good luck. And once again not sorry for my maybe sarcastic tone earlier, it was mainly concern about the school and stuff.