Planning permission or permitted development?

I'm looking at doing 2 new projects; a garage (A) and a kitchen extension (B)

House shown in brown, front door faces the road, end of terrace.

As far as I can tell the garage conforms to the requirements to be permitted development except for maybe this one
No outbuilding forward of the principal elevation fronting a highway

The extension is a similar story. Ticks every box except maybe this one:
No extension forward of the principal elevation or side elevation fronting a highway.

Does this apply to the front of the house, facing the road or is the back of the house facing the lane included? The lane is not marked as a road or bridleway but does have access from both ends and has a fair bit of passing traffic.

Thanks
Nick

The principle elevation is generally the front.

A highway is generally a road in common use by the general public.

If this lane is not marked as a highway on OS or LA plans and if it is not a LA maintained lane, then it's safe to assume it will not be a "highway" for planing purposes.