It's 1am, and to celebrate I've ordered some bits and bobs from Aliexpress for this project, just to try out some options:

• 20x4 i2c lcd screen
• 16x2 i2c lcd screen
• 2.8" Nextion touch screen
• Micro SD card modules

As previously mentioned I'm going to try two versions of this; one with an lcd screen and one with the Nextion touch screen.

The Nextion will allow me to design smell great gui screens and menus, which can be called/requested from the Pro Micro via Serial.

If can get the Nextion one working I think that would be a more useful option as it takes the handling of menus away from the pro micro as such. The lcd screen could always be added to the expansion port if that type of display is required :-)