Interesting, that trace log I posted isn't reflecting the correct version as I have 5.0.2.5 x64 installed on both.
The main BI, the one with the cameras and doing the recording is running as a service. My client side BI wasn't running as a service, (it didn't occur to me to set it that way) but now is. I'll give that shot, and in just some very quick testing does seem stable. Thank you for suggesting that.
The irritating thing now is how the client side BI is only showing a single camera at a time in the main window though "All cameras" is selected. Hopefully this turns out to be finger trouble.
Edit: YUP 100% between the keyboard and the chair, I had selected "solo camera"
Edit 2: The second install of BI is now performing really well now that it's running as a service. Very happy with the purchase of the second license.