I'd appreciate any advice or experiences.
Our NDNs are currently developing an extension. Their property had changed hands twice, once in 2009 to "interim owners" and then in 2016 when they took ownership.
The planning permission was granted in 2006 with a 3 year deadline to commence work. At some point, we don't know when, a foundation and 2 courses of breeze blocks were laid, then nothing done until our NDN started their building work in winter 2017.
Clearly the foundations and blocks were started to ensure compliance to 3 year deadline was achieved, but we wonder if that work was started after the expiration (maybe by the "interim owners" after 2009), could this invalidate the permission? If so, could we take issue with the Planning office (eg if no Buildings Control inspection report submitted after the foundations laid proving the work started in due time?)
In a nutshell, are planning permission 3 year deadlines indicative only or a showstopper?