I've found what the popping like noise was!!!!!
There was a noise gate activated on one of the sends in the session I have been doing all the testing in
It was on a high threshold and was sucking out virtually all background noise apart from the odd random bits getting through and sounding like pops!!
I am SOOOO sorry for wasting the time of all those that have been extremely helpful in giving their time to post suggestions for me to try!!