Old boss wouldn’t serve me alcohol because I didn’t have ID even though they know I’m almost 30 as it was 10 years ago I’ve worked there when I was 20?! Is this legal to refuse when they know I’m overage?

I do understand policies are there for a reason but come on?! It’s been 5 years since I’ve worked in this store and since leaving I’ve never once got asked for ID as they all know me in there, I also do not by any means look under 23 years old. I can’t help but feel this was a power trip on her behalf. I haven’t got ID’d in years so I don’t carry one normally, I had a scan of my passport which didn’t suffice. Obviously it’s not important but this happened in front of other customers and I was made a show of!! I do my weekly shop here and always grab a bottle of wine but I’m considering switching stores now to shop.