I could not get the HSERIN to work....probably timing and RCV stack overflowing. I can't see how I can use the interupt because I don't want to interupt the program.....the motor/thruster commands must take priority. However I did fianlly manage to get the SERIN/SEROUT working, it was a stupid mistake in my program - the jump to statement was pointing to the wrong place. Would like to use the HSERIN though at some point I think it would give better control and think it would also allow me to reduce one of the additinal PCB's.
Thanks for your help