The other thing you can do to get a bit of a better idea - your solar inverter software will list the voltages that the inverters see for each phase - and they are usually pretty accurate.
See if you can match them up that way and then move a load around like a kettle or a clothes dryer (with an extension lead) to get a better idea of what phases are what.
My board was very badly done initially and in the end after messing around like this when i started with the IOTAWATT - i got my sparky back out - showed him what i had found and he agreed with me that colours had not been run properly over time - ended up giving me a discount to redo the whole board correctly and tidy up all the crap
Craig