Thanks for both replies.
Yes I see that PLX-DAQ is quite alive on this forum (as opposed to the PLX website).
I've started to use it and am beginning to understand the code. It's cool.
I've been exploring with the Arduino and got it to do stuff with the commands, but right now I am developing a new form to be populated with GPS Sentences as they come in through a USB/Com port. So basically I'm skipping the built in commands and just using the comms framework to connect and get lines for me to process in CustomDevPointLineRead().
Glad I don't have to re-invent all that comms stuff - way above my understanding.