A few months ago we moved to a new house.  The hall, stairs and landing are fitted with energy saving light fittings.  These are similar to pendant light fittings hanging down with the energy bulb fitted but the diameter is larger than normal.  This means all normal lampshades for pendant lights don't fit.
The diameter of the fitting is about 4cm to 4.5cm

Does anyone know where I can purchase lampshades for these lights?

I have tried several internet searches with no luck.

Thank you