Extending the time limit grants a new permission according to paras. 1-3 in CLG guidance November 2009 "Greater flexibility for planning permissions" . Logically therefore they would have to submit reserve matters again under the new outline that is granted as they will not be implementing the original outline but a new permission. However para. 22, as you indicate, says the opposite which suggests the original permission is extended. It is not clear if CLG is advocating the part implementation of two separate permissions, or simply being pragmatic in the interests of "flexibility", and taking a "positive and constructive approach". It would be interesting to see if the guidance stands up in law as it seems to contradict itself. The same diffculties apply to variation of condition permissions under s73 since a new permission is also created as established by the courts..
