No Picture - U2414H via MST from P2422HE

I have a U2414H Monitor connected (display port) to a P2422HE via MST  connected to a Dell Laptop via USB-c which needs to be continually power cycled.

Everytime I connect/power on the laptop the U2414H  monitor stays black.

Powering off and powering on the U2414H  resolves the issue.

Everytime the laptop goes to sleep and both monitors sleep the U2414H  stays black when the laptop is awoken

When the issue occurs the windows laptop can see 3 displays connected, but no image appears on the U2414H display. If I power it off windows see's 2 displays, then I power it on again, then the display starts working.

Its very annoying and frustratingly especially for an all Dell solution. I have Display port 1.2 disabled on the U2414H  in case it matters. I've tried making heads or tails out of the usb-c waking troubleshooting guide but its not very straight forward :( 

Would anyone have any suggestions/solutions.