Well, I have a local that I could go to on my own - I'm likely to know someone who's in - but I prefer not to. (I probably wouldn't get the required 'quiet drink' anyway; some of the guys think that if you're on your own, you want to be an audience for their boring stories!) There are many pubs in town which I wouldn't go into on my own at night; might do during the day. And I would be loath to go into a strange pub in a strange town at night.

There may also be a rural/urban British thing as well. I live in a small market town and a single female drinking on her own isn't 'done', really.