Thanks for these replies.
I have succeeded in using WriteImageFile so that means I am doing less “backwards and forwards” with Images which is good.
OK - Interesting that you suggest opening each cam port in “reverse order” effectively. I already have been trying to open the multiple cameras but in ascending order and, as you suggest I have one TCVImage and one TCVRingBuffer PER camera, but I also have one TCVGrabber PER camera - are you saying I only really need one TCVGrabber to control ALL the cameras?
Even though I have improved the saving, the GetTimestamp is still just returning 0 for every frame.
How do I try Precision Time Protocol, please, as the critical part of all this is the ability to compare time stamps across multiple cameras.
I very much doubt we will be using the hardware trigger option.