Herbert Terry and Sons Cube Light

I don't know much about the origin of this Herbert Terry and Sons Cube Light.  I haven't been able to find a date for it.  The company have a heritage that goes back at least as far as the 1930s, but looking at this design, I think it is safe to assume that this comes from a later period.

The cube is made from black perspex.  Nestled inside is an orange metal spherical light that can be tilted vertically to direct the light. 

It is for sale for £75 on the Spirografica website.