Thanks for comments, but...

I have a film loaded and have advanced it using the winding knob on the film body. There is no winding knob on the main body. The battery is fresh and even if I turn the shutter speed to 1/60th (which should work regardless of battery condition) the shutter doesn't fire. I suspect that the knob/crank on the main body, as well as winding on the film, 'primes' the shutter and that simply winding on the film from the film body does not achieve this. Does that make sense?

Jim