Right of way side path

General Discussion

I live above my leaseholder who has right of way to the entrance door on the ground floor via a patj which is part of my freehold. I propose building a lean to win a door each end only on the brick not over any windows or doors.
Is the exterior wall mine to do as I please ? If not Is there a height say above the interior ceiling as the permitted limit to fix timber to support the roof ?
This is a temporary structure so no planning required
Am I allowed to fix power conduit along this wall with a socket?
For information there is a solid wooden fence shared with my neighbour opposite the wall to which the roof and rainwater will be attached ( within my property )

Thank you