Drilling into outside wall - ex-council flat

drg0nz0

I am an owner of an ex-council flat (council is freeholder). I want to install an extractor fan in my bathroom. I can see that all the council flats have an ugly fan cut into the glass of the bathroom window. The flats that were were right-to-bought clearly missed that piece of work and have no fans, like mine. I would much rather drill a hole in a wall so inside it looks neat with the wiring hidden, and my window clear. 
Question is - am I allowed to breach the *outside* of the wall? I own the whole *inside* of the flat, but I'm unsure if the leaseholder agreement prevents me from doing anything to the outside surface of my wall??
Might ask the council but thought maybe someone here knows. They're probably short staffed at the moment.
Many thanks

MovingForwards

The council own the outer building, you will need their permission to make any changes to it, probably will for the inside of you want to move walls etc.

It will be written in your lease.

drg0nz0

Thanks. The lease is a bit vague, written in lawyer language, but does seem to imply the outside is basically a shell you can't puncture. But then doesn't the same apply to the surface of the window (in which the council installed extractor fans for their tenants)? Am I not allowed to put in any ventilation in my bathroom if I am an owner?? I wish the original builders at least put the air brick in the bathroom and not the separate WC where it is not needed.

MovingForwards

Quote the bit rather than what you think it implies.

The council can do what they like as they own the building.

You own the inside, but need permission from the council to make changes. That's standard in leasehold properties.

Can't turn the clock back and speak with the builders / designers, most properties have quirks that don't work with modern living, even new builds.