I would like to fit a standard blind to my Velux window (model GGL-7). However, it appears to have been fitted for a non-standard type of blind: there are thin wooden rails on each side, and an extra piece of wood with metal brackets at the top. The extra parts have been painted over, and look like they would be difficult to remove without damaging the frame and/or glass (although I think I could remove the two metal brackets, as they're just secured with screws).
The top of the window (with the opening handle) is on the right-hand side of the attached picture.
Is it possible to fit a standard Velux blind to this window without removing the extra parts? I'm concerned that there might not be room for the side rails, and that it may not be possible to screw the blind cartridge to the top of the window with the extra bit of wood in place.