Polish in Britain - will I get decked if I speak Polish to these people?

...and of course, there was always my idol, Joseph Conrad nee Kozlowski (??) going back over one hundred years and having learned English in his twenties as a young seaman, who became even as great a stylist as pure Beefeater Brits like Hardy, Waugh or Graham Greene (despite the fact that apparently from contemporary reports back then, his SPOKEN English was mired in a thick Polish accent and he made many mistakes!)

Like all great authors his work was very carefully edited and proofread, certainly by his wife (a remarkable person), Jessie.

Someone's second language is never quite like their first,and even if someone speaks a beautifully they may not write with quite the same level of proficiency or vice-versa.

I wonder if the OP has also encountered a cultural issue; Poles can be very warm with friends but cold and wary about strangers.

The same for every nation: the outsider's an enemy until he shows himself to be a friend (hence the custom we inherited from the ancient Romans, namely handshaking - does the stranger to whom you extend your hand bear a weapon with which to do you harm?).

:-)