Indeed not many.
Indeed, and I come across Americans more regularly than Brits. Most of the Brits here are clinic patients and can be found hanging around Magnolia Park and Tesco there. I would say there's approx. 2x or 3x more Americans here. There are also a small number of Indians (mostly IT staff), Spaniards, Middle Eastern and, of course, probably a few thousand Koreans.
I'm always excited to hear a British or Irish voice somewhere, but sadly it's a rare thing and usually limited to a stag party in the Rynek.
The last time I met any Brits they were in a large and very well mannered group leaving Spiz, each said thank you as I held the door for them. Sadly, don't hear thank yous nearly as often from Poles. They were probably business people for one of the IT firms here. Following that, there were 4 or 5 younger ones in a restaurant, they seemed to be employees of somewhere. Very few, usually, in fact I am not sure they even number 50. The reason for the low numbers is that salaries here are very low compared to the UK and elsewhere, I guess.