Hey guys,
I was helped to find the answer with this yesterday by Zoltan from the Resolume forums. The first suggestion that was made was that the sections of 'if' statements should have each analogue read be greater than threshold, as the way I have it in the code above, when the reads were being done, only the last sensor had to be greater than threshold based on what was there.
Eg
if (sensorValue1 && sensorValue2 > threshold)
should be
if (sensorValue1 > threshold && sensorValue2 > threshold) etc
The main thing that we worked out together was that the reason Resolume was being caused to crash was because I'd been allowing it to output midi back to the loopmidi virtual midi port, so this backchatter was what was messing it all up. As soon as the midi out was removed, things behaved exactly as they should again, Resolume could take the midi mapping correctly from Hairless Midi and the triggers worked right.
Thanks to everyone for their contributions on these forums, in particular Grumpy Mike, cheers for all your time & help 
b