This is a difficult one, assuming the ref had a similar sort of view as to the first camera, it looks like someone has grounded the ball in the first instance. In hindsight this wasn't the case, but it would be strange to allow play to continue in that circumstance as white could run the ball out and you might never go back to check if there was any grounding and who grounded it.
I think it was fair enough to blow (on the grounds you thought someone grounded it) consult with AR and TMO and go from there.
well, we do see incidents where (very occassionally) exactly that has happened, and a try has been scored at the other end and the ref has to go to the TMO to - in effect - find out which side scored .
There was an example here debated fairly recently I thought.
In effect I have foiund the answer I initially sou8ght even though having post6ed this I worked it out myself
I suppose the secondary question is really
"at what juncture do you allow play toi proceed with a virew to eventually having to go to the TMo to check?
I can see examples of time out and play continuing for several minutes before the ball becomes dead, time is over but the match in effect hangs in the balance because of the TMO check. etc etc.