If any one is interested, the communication protocol for the older model (non OBD2) Suzuki ECU's on BSII Baleno, Esteem and Gypsy, is available on this site ->
Diagnostics
Using the chart and the byte sequences on the site, I managed to get responses out of my Baleno using a Windows serial port comms program, but didn't have the time to fully explore it. :(