My son wants to move to his nans as we are too over crowded, we are in a 2 bedroom council house. I have 15 yo son, 10yo girl, 5yo girl and 2 yo girl. So he wants to go to my mums, we are not on housing or council tax benefits as my partner works full time but we do get child tax and working tax credits and child benefits. How will it effect me financially if he moves out and who do I have to inform?