I decided to have another look at the loom. Using the loom identification tables in the big manual, I was able to work out what most of the wires were, and how they plugged into the digital dash loom. Everything is fine except I can't work out how to fit the indicator switch, nor the headlight switch, fog light switch, and the other bits that a standard dash would use. I'll ring Westfield about it as I can't see how it will work.