Archie, Many thanks for your reply. After reading your reply above, I swapped from selecting all the fixtures and applying a default, and stepped through all fixtures one by one and applied the default also fixture by fixture. As I did I could see some colour information that way.
All working now - fades occur as expected - some blackout cues had to be rebuilt - but overall we are now working. I've learnt something new - I had never checked or tested the default settings before, and I am delighted it now works as I expect it to.
Only change to workflow is creating new scenes I now have to select a fixture and chose the colour I want first, as of course the intensity comes up black now. But easily manageable.
Reading the old threads led me down the path of 'Select all' Spin all colours to '0' 'Record' 'Home' 'Defaults' - which was not applying default to black on all fixtures.
Changing to 'Select Fixture 1' 'Spin all Colours to 0' 'Record' 'Home' 'Defaults', and then 'Fixture 2' 'Spin all Colours to 0' 'Record' 'Home' 'Defaults', and so on was the solution.
Thanks again
Ian