Yes, I too think 10+ units of alcohol every night would pretty much stop fat loss for me for sure. Especially combined with very low food intake and regular vigorous exercise. (I'm assuming "5 big drinks" is more than one precisely-measured shot per each drink)

The body has to process alcohol even before burning fat. One of the low carb writers, I forget who, calls carbs and alcohol the "metabolic bullies" who just take over and dominate whenever they get in groups. ha.

Also, you need a functioning liver to do low carb, and if you have fatty liver disease from the alcohol, that would not help.

So yah, you asked, and in your shoes I would eat more and have way less alcohol. Maybe the Drinking Man's diet. and if not ready to take a break from the drinking, find a way to enjoy less of it with some days off. I used to drink over the limits of moderation too, so I know what that would take.

Your choice. I vote no confidence on keeping that level of drinking and also fixing your metabolic challenges, no matter what your next plan is.