How can I put wide curtains up here?

I want to make this window look bigger by handing curtains wider than the window.

Complications:

* The ceiling has asbestos so we can’t drill into it.

* The coving is in the way of the top of the window.

What I’d like to find are some curtain rail holders that drill into the wall and raise the curtains higher but I can’t find anything like that other than for doorways.

I don’t want blinds in here.

I have seen some curtain poles which use tension to clamp between the ceiling and floor but can’t find them in the right colour. I’ve also seen some tracks which use adhesive to stick to the ceiling but I’m scared of how that could damage the ceiling, if anyone has experience with those I’d love to know!