Although the PCB is fully functional, I thought I should make a list of the errors before I forget:

• Rotary potentiometers upside down - cosmetic
• Toggle switches upside down - cosmetic
• Lug mounting hole for slider in wrong place - non-critical
• Board outline doesn't follow USB and power sockets properly - cosmetic
• Schottky diode missing between 12v supply and Arduino Vin, which was supposed to prevent the Arduino trying to accidently run the motors through it's own power supply - non-critical but potentially damage could be done to the ARduino due to user error.
• LED resister incorrectly labelled as 10K and should be 1K - non critical.