[Spencer]

I'm not sure - zooming in on the 1st picture it looks like lights from the actual corridor outside the studio (i.e. on the other side of the glass wall) that, due to the angle the photo was taken at - are reflected in the glass desk top?

Hopefully someone with actual insider knowledge can clarify!

I can't claim to be an insider, but having seen other images of the inside of BBC Cardiff, they do have those cross-shaped lights throughout the building, and it's clear the image shows exactly what you describe.