I have a Raspberry PI 4B running Octoprint with a Raspberry camera, works fantastic via the web browser or via the local touch screen I have installed, the screen uses two USB ports and the HDMI output however no matter what I do they wont both run at the same time, what I am looking for is to be able to start a print with the local 7" screen then if I am at my computer later check progress, this is using Touch UI as the interface if I remove the screen shows up perfectly streaming via the web interface, if I plug in the local screen it wont connect remotely via the web browser but works perfectly from the local screen
I will upload the logs once I work out how too 
It sounds like you're saying that either the display or the webcam works but not both, right?
If so, then this could be power-related. Also, the 4B has two USB v2 style of connectors and two USB v3 style of connectors (blue). When you're testing various scenarios you should know which one you're plugging into where.
Brought a Mean Well RD-65A today and will wire that up, tech savy but very new to Octopi 
Thanks for your help !!! will look at the 4B too with what you have said
Not the power supply however I know have a lovely looking supply powering my unit, what I find the answer I will let you know
Things tried
- Bigger power supply no change
- Swapping over between USB 2 AND 3 no change
- Booting without the screen then plugging in no change
One thing I wondered is if this is actually possible to do, or disabled as a risk during a print?
I suppose it all depends upon how you connect that. Most of these types are called switching power supplies. If the current requirement across the 5V output side of that is below a minimum point, it will turn itself off. For small projects, sometimes that doesn't work and ends up power-cycling. So if it does cycle ON/OFF/ON/OFF... then it's necessary to add a large resistor (and by large I mean high-power) to drop some of that output 5V when there's no load (when the Pi is off). If you don't know how to find the right value for that then I'd suggest not using that power supply.
That said, in a case like this, you'd want to bring in that 5V to the Pi. Most people might think in terms of using a micro USB cable but this is a terrible idea since those are only designed for 2.1A @ 5V. It would be necessary to bring the power in to the GPIO pins instead using a bigger gauge of wire then you usually would see.
My gut tells me that this is a bad idea to use that big of a power supply. I have one of those for a 60-LED NeoPixel ring because that's what it requires. I was using this device in my project for a period of maybe two months and the input-side rocker switch for that power supply has gone out within this period of time. I have another one to replace it with but you have to wonder what's going on if that beefy-looking switch has internally fried. Maybe the internal LED fried and then this prevents it from working...? /unrelated
There is nothing wrong with the power supply, my background says I know this
Hello Coopznz, did you somehow manage to solve this issue? I have the same issue as you.