Well it definitley works... tried a few other calls, can get the imei number through the call:

dbus-send --system --print-reply --type=method_call --dest=com.nokia.phone.SIM /com/nokia/phone/SIM/security Phone.Sim.Security.get_imei

But still getting the introspect errors.... (Each call throws up one error)... i'm assuming they get ignored, as if i was not looking at terminal, i would never know there was an error......
(Just wanting to make a nice clean app!)