BPRI is wearing a Wescam 24, most likely containing a film or Red camera. This mount can take most cameras and camcorders - which is why it's so large. And, importantly, it can carry big heavy film lenses for 35mm and Red. (Red is a 4000 line camera - as opposed to HD 1080 and SD PAL 625)
The mount in the pic actually has half the globe missing - so they must have been working on the install. Once back together it really is 24".
The 2 others carry manufactured balls : looks like the BBC get UltraMedia (standard def) whilst Sky appear to have spent Rupert's pocket money on a Cineflex HD V14.
I'll get my anorak.