I have found a solve for my issue which was that only the text and
audio rendered and the video remained black all the way through. It is
simple but I don't know why it is set to this on default so that you
have to change it all. The process however is quite simple.
Easiest way is to highlight the whole video track once you have completed it and you are happy.
If you have more than 1 event (multiple events) click on the first
event then use the bar to move to the end of your video in the
timeline, hold down shift and click on the last event. You should now
see the whole video track selected.
Once this is done, hovering your mouse anywhere over the video track
right click and bring up the menu. Go to switches and as you can see in
the picture I have circled in red what is important and the reason why
video is not being rendered.
Now change the option to disable resample below:
and thats it deselect your video and try rendering. This fixed my render issue I hope this fixes yours