Thanks @borate appreciate your help here. Yes, the replacement clips/images are simply the same power point slides just minus the red dot.
I wasn't aware of the lock option and only just read up on it a little before your reply so will give that a try as that may help fix all the changes I have made with the images in place.
I am exporting the video right now but won't be able to review it until much later. Hopefully it will come out fine. Either way I'll be sure to send through an update.