Exactly - there’s no beer duty, so it should be a chunk cheaper (at least 50p a pint cheaper compared to general duty, 2.8% to 5.5% abv). https://www.gov.uk/tax-on-shopping/alcohol-tobacco
One thing I noticed living in a pub was that every time the government put up beer duty, the brewery would add their own price rise at the same time. So if beer duty added 5p to a pint, so would the brewery and we’d have to charge 10p a pint more (or lose money). Of course people complained, but everyone just blamed the government for raising taxes - the brewery themselves got away with it.
The amount of duty per pint is lower than I’d have thought (before I looked up what it actually is these days) - the rest is the brewers charging whatever they can, and the pubs passing on these costs (while trying to make a living).