After some digging through the BA Holidays T&Cs, I think I found the answer as to why no bonus avios were forthcoming. I was aware that similar T&Cs were introduced for the Double Tier point holiday promotion over a year ago but hadn't been realised it applied here also but probably should have suspected. As I'm resident in Ireland and flights originated from Ireland for all 3 trips looks like none of them qualified on two counts. Ah well...

From: https://www.britishairways.com/conte...avios/holidays
8. Bonus Avios are only awarded to Executive Club Members who are registered in the United Kingdom (UK). For flights + hotel or flights + car bookings the flight element of the booking must originate in the member's registered country (UK) to be eligible for Bonus Avios. For example, a registered member from the UK, must start their eligible outward journey (British Airways or British Airways codeshare flight) from a UK airport.