Yes, yes and yes! All those things done and I see the problem. It's not that I can't see any plots, there are no plots to plot! On the side panel, I selected auto-select and display, but the three aircraft that were indicated as tracking must have only mode C and not mode S and it said that no position info was available!
Thanks guys, I'll keep on trying. There's not much traffic around here on a Sunday except for the aero club in their C152's and I doubt if they have Mode S!
Cheers - Martin ZL2MC - Palmerston North