Permitted development refused

[Skanxz]

I have applied for permitted development for an extension over a courtyard and 1.5M beyond the rear wall of the house. It was refuse with no real info on why.
The main house semi detached was built in 1886 and is 8M wide and 10M deep, about 1900 an extension (servants quarters) 3.5M wide and 7m deep was built. 1.5M behind the extension is a livable annexe 4M wide and 5M deep which was originally where the gardener lived . This creates a courtyard to the side of the extension leading down to the annexe 3M wide and 8.5M deep. All parts of the house and annexe are pre 1948.
The plan was to cover the whole courtyard down to the annexe 1.5M beyond the rear wall of the house, add 1 dividing wall at the end of the extension to create a entrance/cloakroom to the annexe and to remove the side wall of the extension to create a large room.
Image of plan is not the full plan that was submitted.
Is there a legitimate reason that it can't be done under permitted development or have the planning department not understood my plans.
Thanks in advance.

 

[^woody^]

Permitted Development can't be refused, and you don't need to apply for it. Otherwise it would not be called "Permitted Development"

If it's not Permitted Development, then you need to apply for planning permission, and if refused, you get told why.

 

[Notch7]

Is there a legitimate reason that it can't be done under permitted development or have the planning department not understood my plans.

I would say its not permitted development

under PD you can have a side extension going as far as the rear of the house + you can have a rear extension the width of the rear going back 3m

that leaves a square section that is not PD

 

[tony1851]

As dimension (c) is more than 3m from a rear wall, I'd say that would not be permitted development.

Yes, it would have helped had the council advised you why it refused the LDC.