iPad Pro (2nd gen) and Stages SB20 - connects and then 'No Signal'

So been using Zwift and my iPad Pro for a while and a few months back I swapped over to a ATV4K and screen and all is well.

I’ve needed to swap back to using the iPad Pro (12.9" 2nd gen) and it’s been almost impossible to get a stable connection. It finds the bike and all the other sensors (cadence, power, HR) - but once you connect within the pairing screen - within a few seconds it goes ‘No Signal’. Trying to unpair the device and re-pair then leaves me in a state of not being able to ‘see’ the sensors again. I have to reboot the iPad.

Everything’s up to date, ATV4K is unplugged (thinking perhaps it was trying to connect) and nothing else (be it BT or ANT+) is connected.

If I try and use my iPhone 12 Pro - it all works perfect. So either an iPad problem - or Zwift on iPadOS?

Any ideas?