All renewal forms need to be returned to HM Revenue and customs by the 30th September 2005. If you don't return your form by then, your claim will stop and you will need to make a new claim. This can only be backdated by three months.
If you are waiting for a final income figure for the previous tax year, you should provide an estimate for now, and confirm the actual figure later.
To find out more about tax credits and what you can do if you have been overpaid look in the hereforadvice Directory.