You're moving to Poland and you also play saxophone ;)
I recently came back from the UK to Poland as well, the reason being... money. (most people will say - wth?) But in reality, which country gives you better possibilities, depends a lot on the conditions you wish to live in, and the job you're having. So it's never easy for me to answer people who ask me "so in which country is the life better?"

For a minimum-wager it must be UK (hence such a big number of immigrants is actually taking the lower paid jobs), but once you pass a certain level of your carrier and you might wish to live in a city center or on your own, calculations get complicated.
Those things cost a lot in the richer countries and barely any young person would be able to live on their own e.g. in London.