If you open the front doors and look straight up there are 2 holes (on each door) that look like they have screw threads. Only noticed these when giving the car a clean earlier.

Firstly are these normal, and secondly what are they for?

They are for attaching roof rails.

On the inside of the door? (I've never had them so that might be a stupid question)

Yes on the inside, the ends screw vertically into these as there is nothing on the roof of the car to hold them. My Audi is exactly the same.

Brilliant thanks.