Oh no the horror!
After testing the motor driver and writing some code to control the robot based on line sensor input, I tried it out... Nothing seemed to happen so I double-checked the PICAXE 40X1 schematics with my robot's wiring and I have completely forgotten, that the two L293 pins for enabling motors should be wired to PWM outputs (Noooooo!). I guess I'll have to get my soldering iron heated and perform surgery on poor Pete. I was so happy that all the hardware I had wired just worked the first time... and the I go and do something like this *sigh*.