Looks like there could be a wallbox in the bottom right of that that photo ?
Yes. PQ has lots of 'presentation spaces' pre-wired. That's been 'a thing' in BBC buildings for decades - dating back to BBC Oxford Road and Pebble Mill buildings.
NBH has copper and fibre connectivity in most areas.
Wired for Triax or general HD-SDI, a lot of the studio cameras output 3G HD-SDI so that wouldn’t be an issue (especially with maximum lengths of digital triax).
A mix - though PQ is SMPTE fibre for cameras, not Triax - so I'd expect some SMPTE fibres, rather than triax, (to run cameras over) that would go to a patch position to allow them to be patched to CCUs. 'Proper' cameras don't use HD-SDI or 3G-SDI for interconnection - they use SMPTE or Triax - as that carries prompt feed, reverse vision for the operator to see the programme and feed a vanity monitor (or in some cases also a secondary feed - like an ME bank to line-up and inset shot etc.), talkback, programme sound (so the operator can hear the programme), tallies etc. All that happens over a single SMPTE fibre connection - and that also powers the camera. One cable.
SDI connectivity for cameras is really limited to cheap news installations where brick cameras or cheap PTZs are used. The more features you add to the camera, the more cables you end up looming together, so much so you end up with a horrible snake of a mesh-wrapped umbilical (or worse - lots of taped together cables)
(Though many people run prompt hoods from a separate power feed rather than the camera power outlet - to avoid a failing prompt hood tripping the camera power. So even with SMPTE or Triax you can end up with a loom still...)
There will probably be some SDI (or fibre-to-SDI converters) to allow for in-vision and out-of-vision monitors. Some audio connectivity - both copper and possibly fibre connectivity to allow a stage box to be connected, and also possibly some RF or RF-over-fibre routing to allow RF mics and IEMs to work)
Fiber I assume could be connected to a multiplex system (like from Multidyne were they bought by Belden ?)and transmit almost a whole studios worth of cameras.
Not sure why you'd bother with that - just patch SMPTEs between camera heads and CCUs? Why would you need to multiplex it? Fibre isn't that expensive to install when you build a studio centre.
And now I think Grass Valleys new LDX100 camera you’re can just plug it into any 10 or 25GB fiber connection and connects to the network.
Yep - if you buy the Direct IP system then the camera can be plugged into a SHED-style device to inject power at the camera end, and passively convert the SMPTE cable feed to an IT connector (SC/ST etc.) and connect to an IP-switch. Somewhere else on the IP network will be a corresponding XCU (GVGs name for a Direct IP CCU) that you connect to the switch, and that has audio and video connectivity (baseband or IP) that you would expect. if you don't need any of that baseband functionality then it's possible that you can run a GVG camera without an XCU.
Inspector Sands and valley gave kudos