ok I found the solution, so for anyone else with an icom PCR scanner it's the packet socket on the back of the device. Connect a mono-to-mono audio cable (3.5mm) from the (correct) packet socket to the mic input on your PC. Spend about 10 hours setting the mic volume to about 40% of the full level for an incoming pocsag signal. Use the default settings in Interface/Setup the PDW program - make sure your mic input is selected in the soundcard box. This worked for me, and I had a good laugh when I read:
'incident at starbucks nottingham, assault with cone'.