we have 2 kids
They're the starting questions: how old are they and do they speak Polish? If they're five or under, you can move them without too much of a problem. At that age kids learn languages pretty quickly and in a year or two they'll be able to hold their own in the classroom with other kids their age. But if they're more like 11 or 12 and don't speak Polish, you're basically setting their lives back by at least two years because it will take them that long to get fluent enough to study in Polish.
We are thinking of moving to Lublin and trying to find work for me there.
Do you speak Polish? If not, what job can you do that a Polish-speaker can't do.
Lublin is a great town, I like it a lot, but there are not many English speaking visitors to the place (which is one of the reasons I like it).
does the Polish government offer any financial assitance for families like us?
No.
However, you should be able to claim UK jobseeker's allowance in Poland for some time. I'm not sure about the details though.
Also can we recieve hospital or free healthcare in Poland?
Yes, but only if you're employed full-time (unemployed people can get it too, but they have to have paid into the system for a certain time).
Your other option is to sell the property in Poland.
I'd be thinking sell the property and invest the money in training in the UK for a trade (plumber, chippy, etc).