Hello again
First the solution:
The clue was ‘Head in calls for attention after his first class’
the answer is HOI POLLOI
Why?
Well, ‘calls for attention’ is OIS i.e oi (as in Oi you) with head in i.e POLL (another term for head as in Polling which is a head count) all following his start H (first letter of ‘his’) gives class (class of people)
The latest clue is ‘O, I’ve never done it before’ 6,9