UK Child benefit and tax credits are paid there (and elsewhere) too:
http://www.telegraph.co.uk/news/ukne...Europeans.html
Of course you're probably free to work in Poland and claim their version of CB for your kids here but I doubt it'd be quite as worthwhile somehow. IIRC UK CB for 2-3 kids equates to a reasonable public sector salary in Poland so add tax credits on top and you're doing quite nicely thanks...