From what I understand a way a lot do it out the gate to get some $$$ back in the bank is the new tax year runs april to april, just bank all the tax money to earn interest, then in april 2009 now submit tax form and that gives you until april 2010 to pay it right, by which time you have earnt 2 years tax money all banked earning interest.
I could however be wrong on that and as I am still yet to go see my accountant when the $$$ start to come in the door,, so we will see the best way to do it,, but yea, def dont not pay, they will repo your kids!