Updated Apple Watch to 10.4 and it no longer tracks my activity

I updated my Apple Watch to WatchOS 10.4 last night and this morning it has stopped recognising any movement/motion. For example, it no longer 'wakes' when I raise my wrist despite 'wake on wrist' being turned on. It also doesn't read my heart rate or track any calories burnt, steps, standing hours (no activity at all). I have completely reset and re-paired my watch with my iPhone as well as restarting both of the devices and nothing has worked. The sensor on my watch is still lit up green so I assume that it isn't broken so I am thinking that this might be as a result of the software update! Has anyone got any tips on how to fix this... I also know someone else who has had this problem since updating to 10.4!