£25000 is below the average household income in the UK (which is above £30000 ), that would need to be complemented for your family to live comfortably.

If you check with a tax calculator ( www listentotaxman com ) you'll be left with £1800/month . You could try to budget using the websites of well known UK supermarkets (Sainsburys, M&S, Waitrose, Tesco, etc) by checking how much your current shopping would cost over here, checking rentals (google for it) and for other major expenditure so at least you don't arrive blindly if you decide to come.

I have to say that £1800 for 4 people sounds pretty scary :-)