Reading up to answer my question it seems that Blender once had an offset setting in NLA for use in conjunction with Repeat but that has been replaced with something else. I can't find out what it is.
I tried making a simple animation of the default cube of just a few keystrokes using the timeline and then using Cycles with Offset in the graph editor to repeat the action. Fine, but when viewed in the Action Editor, the repeat cycles cannot be seen and when pushed down to the NLA, the action strip is just the basic timeline animation with no repeats.
If I want to make an action strip comprising say 20 repeats of a cycle WITH OFFSET how can I push that action into the NLA or its cache so I can then use the full strip at will?