Update: I've had a few weeks on which to observed myself on the ranitidine, and unfortunately, my conclusion is: no effect. My pattern is pretty variable from day to day, so it takes a while to get a good feel for whether there's been any overall change. bummer, eh?
It's available without a prescription at 150mg in the US, with the recommendation to take it no more than twice per day.
I think the UK is more of a nanny-state with regard to healthcare than the US. The NHS is still very much run along the lines of "Me clever doctor, you stupid patient, you can't be trusted". It annoys the c**p out of me.