No, that is not it. Whilst the indemnity Insurance referred to is paid up you can recover your costs and loss in the event that your local Planning Authority refuse retrospective planning permission for the extension and/or enforce demolition or alterations. The insurance will have a limited life, usually 12 or 24 months. During that period it is advisable for you to apply for retrospective pp, otherwise at the end of the insurance you carry the risk alone. There is some information at
http://www.planningni.gov.uk/Devel_Control/Pla nning_System/Enforcement.htm . Budget between �300 and �1,000 depending upon the amount of information/drawings/site investigation the planners require.