Many thanks for @rickr000 for lending me his Lynx to fix this issue! It's only applicable to early Lynx 2 machines, and you'll know if you're affected. The menu will just be a black screen.
This is an interesting hardware incompatibility with LCD mods and old Lynx 2's.
The Lynx GameDrive is back in stock in the UK at @RetroGamerStuff and @retrotowers. You can also pick up a NeoPocket GameDrive while you are there as well.
And before anyone asks, yes, the Jaguar GameDrive will be following in a few weeks.