On Monday, 6 May 2019 20:41:37 UTC+1, David WE Roberts (Google) wrote:
Sadly a full width shelf across the window might be counter productive. :-)

Or it might be the ideal place for a pot plant, or anything you want to expose to UV light.

Probably trunking across the back to hide the cables.
Hmmmm.....use the excess to make matching trunking?
Or just do it the easy way with plastic?

Cut in some cable access portholes so the wires can drop down out of sight.

Owain