Your council tax band will only change if there have been any alterations to the property since the last revaluation in 1991 - when you sell. If you have put any extensions etc. during the time of your ownership, the buyer will automatically be rebanded. You may well find the answers to council tax questions, bailiifs and court actions etc., on the website of the Isitfair campaign
www.isitfair.co.uk This is a non party political campaign, calling for the reform of the council tax system. There is sure to be someone who will answer any questions you may have.