As above, no effect on “normal” alcohol, just the cheap cider, buckfast etc.
Multi buys and bogof type deals were made illegal a few years ago under a different piece of legislation, as were happy hour promotions.
Couple of interesting changes is that a bottle of cheap own brand vodka is now the same price as the branded equivalent, and small corner shops are the same price as big supermarkets.
Will be interesting to see if it makes any difference.