On Mon, Mar 08, 2021 at 08:27:30PM +0000, Chris Packham wrote:
[ ... ]

quoted

Other than that, the only other real idea I have would be to monitor
the i2c bus.

I am in the fortunate position of being able to go into the office and 
even happen to have the expensive scope at the moment. Now I just need 
to find a tame HW engineer so I don't burn myself trying to attach the 
probes.

A bit unrelated, but you can get scopes connected through usb which are
quite low-cost (like in the $100 range) and good enough for i2c testing.

Guenter