I made a few Microbit Robots for the local library coding class.
This one was printed from scratch.
These two used commercial chassis.
They all use a homemade dual motor driver I had posted on Instructables years ago. I originally designed it for CNC use but it works better in a bot.
The first controllers used the accelerometer for steering. Later I turned this old yard sale find N64 controller into a microbit host.
The board is a perfect fit