In general, what I can't understand is why when I want to transpose One semitone it does two i.e. one whole step.

I was able to find some success from the Edit page, Transpose. There it seems to work properly.

But on the Notation page, Opt button, strange things are happening.

In Sibelius, when you transpose it asks which interval, minor 2nd, Major 3rd etc. To me it is much simpler. Or perhaps I am missing something still.

Thanks
Jeff