Is it possible perhaps a Daft question

Looks like you pretty much have it in hand and yes Fritzing (even with its bugs) is impressive. The 4 values comment relates to what I think the leds are intended for. Each servo seems to have 2 leds (4 colors) rather than just one. I think the intent is that the leds go in a signal by the tracks at the switch one on each possible branch. If the switch is set to that branch the led would be green and on the other branch the led would be red (to indicate that you shouldn't proceed). That seems to me why the numbers are there and why he needed 3 shift registers. If you don't want to do that you can probably use less leds and at least one less shift register. Your leds are the typical Ebay type, no real information but at least cheap so you may need to experiment with the 220 ohm resister values. You may want to start with something like 470 ohms and see how bright the led is. A higher resistor value will make the leds less bright and a lower value (within reason because too much current will damage the leds) will make it brighter. I think your analysis of the code is correct, at startup it cycles all the servos and then waits for you to push a button and then changes the position of the switch. You may need to adjust the two values (currently 93 and 117) to get your particular servo to move the correct distance. If you run in to problems, post and I'll try and help.