Fitting roller blind brackets to an upper surface of recess

[Caz6]

Am sure there's a way to do this, I just can't think of it so need your help...

I'm fitting a roller blind's brackets inside a window recess. I could fit the brackets to the UPVC window frame but am limited on space and it means the blind will hit the handles when down. So, I want to fit the brackets to the upper horizontal recess but can't get my head round how to drill the holes as there's no space for the drill - the holes are approx. 1cm from the vertical recess and my drill is way wider than that.

The blind's quite large & heavy so I can't just tap nails in instead of screws and besides, I want it to look good )

Any ideas???

 

[big-all]

attach to a timber batton off 3x1 or 4x1" [19x69/19x96]and the opening length then screw/ no nails to the top/lintle

 

[foxhole]

You could put the baton on the frame to build out and allow blind to pass handle?