EmulationStation blank screen after installing Picade Software

I have built a Picade 10", and initially Emulationstation boots fine. But once I have installed the Picadehat software using Curl as per the instructions, the screen goes blank before you get to the Retropie loading screen.
After installing the Picadehat software it warns that it does not detect Retropie as being installed - I initially used the Retropie 4.8 image as it is the latest. I then tried a Retropie 4.7.1 image, but the Picadehat software refuses to install, saying that the 4.7.1 release is ‘oldstable’.
Can anyone help please, as I don’t understand why the Picade software is not working with Retropie?

Disregard above!! Having followed the instructions (almost) to the letter, I was caught out by putting the HDMI cable into the RPi 4’s HDMI socket furthest from the USB-C socket. It’s now apparent that the instructions mean furthest away from the 4 USB-A sockets. So I had it in the wrong one. Hope this helps anyone else struggling