Wow Simon, that situation with your kids sounds tough. Can I ask a couple of questions about the drinking?
1) Are you just going to the pub alone or meeting eith friends there? Having someone else to talk to is a) good for you anyway and b) if you’re taking to someone you might not drink as much (difficult to put drink in whilst words are on thier way out) or at least slow down since your talking too.
2) Try having shandies and/or alternating soft and alcoholic drinks? If the pub is where you’re going for socialising and that’s how your letting off steam/pressure/stress then I reckon any attempt to just ‘stop’ will not work and only leave you more miserable. Tempering the alcohol intake whilst keeping the enjoyment is a good start and then, hopefully, you can start to replace the pub with something else to do (sport? Hobbies? Just taking a walk?).
3) Is anything likely to change soon? Like visiting/access arrangements etc? It will help yo try and work out, even if only in your own head, whether this is a holding pattern (and therfore the pub/drinking is just a temporary “solution”) or the new normal.
I hope some of that might be useful to think about, or at least good to know someone saw your message and is listening.
I hope things get better for you.