Well I did it and it seems to work for me. Tested it with the key off and the hazard works, but the Cruise didnt. Aaaagh. Then realised it needs to be in drive mode to work. Phew! test drive says it works.
I did the changes at the headlamp, opening up the connectors, testing for contacts till I found switched pair, used a fine nail to remove the yellow insert and then freed the pin. That way I can switch it back, ie no soldering etc. Its a pig to reach all the wires and I ended up modifying the headlamp bracket to make it easier next time (?get a life?)
Amazing to have better control of cruise, but it becomes obvious its fairly crude and could do with the software upgrading to car cruise levels along the suggestion above using the Mode key. Also the current algorithm is crude, it doesnt make a constant speed up and downhill. Probably needs full PID algorithm or constants upgrading.
So for me, the mod is brilliant. Dont suppose anybody could tell me the wires at the main controller board to swap instead of what I did?