The funny thing that most UK people don't realise is that most immigrants coming over don't understand the benefits system. It's not even a consideration for them. They come to work and make a better life for themselves and their family. So it makes me laugh when the Daily Mail et al make it sound like they all rock up looking for a house & benefits.
My wife is from Latvia and came over to the UK seeking a better life nearly 9 years ago now. Her sister is also here as are a couple of her cousins.
Through my work I've also regularly visited Krakow and work regularly with the Poles there so I've some experience of Poland.
What I would say is that if you come over then initially you will have to start off working at the bottom. Your qualifications (whatever they are) won't mean anything here. One of my wife's cousin is a engineering graduate but started off working graveyard shifts at Morrisons warehouse.
But if you are intelligent and willing to work damn hard to work & study then life will get better. He now is qualified as an electrician and has found a much better job earning much better money.
Same for my wife. She started off working shifts in factories doing the menial jobs that our local population don't want to do whilst claiming there are no jobs.
Now she's a manager for a company that sends carers into the community and she regularly pulls her hair out at how hard it is to find reliable people.
My wife's family who are here will all agree that the standard of living here is much better now than back 'home'. Working hours aren't anywhere near as long as Poland. I've seen the hours my Polish colleagues work and they can keep them.
That said and done....you currently have a fairly good standard of living in Poland. So I think you need to decide based on your future prospects in Poland and whether or not you are willing to start from the bottom again at the age of 30 with kids in tow in the UK.
Only you can decide that.