I'm also surprised that you'd get severe withdrawal symptoms after a relatively short period on 10-15 units/day. I thought that was limited to 'serious alcoholics' getting through a bottle of spirits per day, really.

I've done significantly longer periods averaging maybe 10 units/day, and quit a couple of times with no problems other than feeling a bit tired/achey and craving a beer in the evenings. Annoyingly, I'd managed to stay off it entirely for over a month before the lockdown hit, but I'm back on it now ('fuck it, the world seems to be ending, I'm going to have a drink...'). Still managing a few days off a week for now though, trying not to fall back into drinking every day.