I have figured this bit out myself: clearly I am a moron.
Having established that, can someone please explain to abovementioned fool WHY every book reader** other than Calibre View completely ignores the CSS added by either Polish or Modify ePub, regardless of what is in the template and/or the CSS? To make sure it's not my custom templates to blame, I reverted to Calibre's jacket resources to no avail.
** I have tested with Nexus 7 Lollipop and my generic Chinese knock-off phone - using Mantano Reader in both cases - and ADE 3.
I'm sure way back when I used to get matching results in Calibre and Mantano.
This should probably be a separate question, but seeing I'm here... in pursuit of happiness I've overwritten my own templates etc. and now can't remember how to add swop LN/FN to the template. If nothing else, getting that back will make me happy.
TIA for all wisdom