What tax credits you receive as a married couple depend on your joint income - however if you are not living together this could be different. Give them a call and ask them to give you an estimate on the benefits you would receive. Bear in mind that they often get it wrong though!!! Also the credits system run from the previous April - so that might give you more time to sell whilst your credits remain the same. Trouble is that the tax credit system is it's own entity!!!!