From my own experience. Get in there straight away before a CPO is issued. You will in most cases also have the right to appoint your own surveyor at the council's cost in addition to the one appointed by the council. He will usually work in your favour and serve the council with comparable sales in your area for a fair price. Remember the state of your flat including double glazing and central heating is taken into account when valuing your flat so make sure as when you would sell your flat on the open market that everything is in tip top order when the surveyor comes round. Good luck!