What kind of shade will fit this light fitting?

[JessieMcJessie]

We have just moved. In the hall, this light sticks out of the wall horizontally. I want to get a cheapish shade so that We don't have a bare bulb but am flummoxed as to what would fit it. Don't even know what to google - "wall light" just gives me light fittings to attach directly to the wall.

Any suggestions?

Try typing in "wall sconce clip on half shade"

or "half shade"

Thanks centigrade! Have found one in John Lewis online that looks like it might work.