My vote is to stop. There is no upward trajectory to heavy drinking, it's all downhill. 30 - 40 units a week is heavy drinking. About triple the current health recommendations, as I'm sure you know. I'd guess there are many weeks above that if you're drinking hard spirits. I found it nearly impossible to keep track of my intake after the first two or three.
Why not stop completely - maybe start with a year commitment to see how much improvement you'll see in every area of your life?
First, it's not going to be that easy and you'll quickly see where you stand without it.
Nothing good is in the bottom of a bottle. Not one thing.
As far as the definition of "alcoholic" - it's a lot of things. You will have to make that call, but you're way above casual social drinking.