once these Pole's make enough money in UK many will go back to Poland with their family and money
I don't think it's quite that simple.
I'm unsure of the figures regarding the number of Poles currently in the UK, or how many have returned to Poland since 2004, but of the Poles I personally know, none of them have returned to Poland with overflowing pockets or enough money to buy a home or land. The ones I know that have returned have done so because the UK wasn't what they were expecting or because the work situation was difficult due to language problems.
Living in the UK is expensive, and although most of the Poles I know are better off here than they were in Poland, there certainly isn't scope for saving loads of money, unless you are fortunate enough to have very good language and transferable job skills, or you want to live under very bleak conditions. Even coming to the UK with a university education doesn't guarantee you a job.
I'm certainly not surprised by the so called Polish baby boom in the UK. If families here have more financial stability than in Poland, then it makes sense. And if the reason for coming in the first place was due to the low wages and unemployment in PL, why would people who have chosen to have families here, return? More to the point, I doubt they could afford to return that easily with a family either, especially after living here for years and being out of the job market in Poland.
I'm not sure what the answer is, but Poland needs to provide more incentives to keep its citizens there. With low wages, high unemployment and poor childcare, it's a no brainer why Poles are moving abroad and staying there.