Thanks so much to @minute and @Savasten, you’re both stars!
I did go through a little more panic, as on reboot there still wasn’t any output, and then I had the idiotic idea of updating the brightness via the file used in the steps, but then it immediately rebooted and wouldn’t boot via the OLED menu, but after flicking the standby switch off and on again it booted, and with my screen now working great!
Edit: still getting used to the little keyboard (typos)