Thanks to those who responded to this post. I have today received
clarification from the Planning Inspectorate as follows....
If a retrospective application is refused or not determined, an
appeal can be submitted within 6 months of the date of refusal or the
expiry of the period for determination. The power to grant permission
at application stage is contained in s73A(2)(c) and at appeal stage in
s79(4) of the 1990 Act.
If they submitted a retrospective planning application after the LPA
issued the enforcement notice, the LPA may decline to determine
the application under section 70C of the Act (as amended). If that is
the case then they cannot appeal against an LPA's decision to decline
to determine their planning application. This is what Paragraph: 013
Reference ID: 17b-013-20140306 is referring to.
On the information provided it is unclear whether an enforcement
notice has been previously issued and if not, Paragraph: 013 Reference
ID: 17b-013-20140306 does not apply.
Finally, I do appreciate that the wording on the GOV.UK page maybe
misleading or could be misinterpreted, however, The Planning
Inspectorate has no control over what is published on those pages.