OP, IMO need to get back to the NOR.
An appeal is against the authority's Notice of Rejection which IMO is exactly where you start.
A suggested draft to knock around..
Dear Sir,
I refer you to the authority's NOR which states their reasons for rejecting my reps as follows:
[the] vehicle is on 'Unnamed service road to north of county court in an area with restrictions of no waiting and no loading at any time indicated by a sign and no observation period is required.'
The sign in question is referred to in the next paragraph as a Restricted Parking Zone. The authority claim that this sign also carries additional restrictions of 'No waiting at any time' and 'No loading at any time'.
I also refer you to the photos in the NOR which clearly show that my car was parked adjacent to double yellow lines which extend for the whole length of my car.
When the driver parked they did so in the full knowledge of the DYL but did not see any kerb markings in the vicinity of their car to indicate that loading restrictions were in force. Therefore they displayed a BB in the required position believing they were parking lawfully. At the time of parking they were not aware that they had, as the authority claim, passed a Restricted Parking Zone sign.
Although the authority's response refers to the presence of this sign, they have not included a photo neither have they indicated where it is located.
I submit that the contravention did not occur for the following reasons:
If the authority wish to rely upon the presence of road markings to convey the restriction, then their photo, which does not show any no loading markings in the vicinity of my car, shows that the alleged restriction was not conveyed as required.
2. However, if the authority wish to rely upon a restriction conveyed by an unspecified Restricted Parking Zone sign, then this restriction has not been conveyed as required because, as I discovered after the event, an RPZ may not include yellow lines of any restriction. It must surely follow that as an RPZ and yellow lines are mutually exclusive then the zone has not been marked as required.
3. The adjudicator will see from my attached screenshot captured from Google Street View that the 'unnamed' road is in fact Tackett Street and as such the PCN misstates the grounds (by virtue of not giving the correct location) and, yet to be verified, there is no such restriction relating to Tackett Street in the authority's evidence.
By 'marked as required', I refer to what I understand are the provisions regarding 'traffic signs' in the Local Authority Traffic Order(Procedure) Regulations.
My references to markings which apply to Restricted Parking Zones are to what I understand applies by virtue of Schedule 1 to the Traffic Signs etc. Regulations.