Yes, the information is buried away on the BA site, but I found this (screenshot shows Avios awarded for flights on Aer Lingus and Emerald Airlines)
View attachment 145400
So it looks like your fare class simply isn't included for whatever strange reason. It is very odd, but if I understand correctly, it seems that there's a difference between the Aer Lingus routes out of Dublin and those operated from elsewhere. If I'm guessing, it's that Aer Lingus might be taking the revenue risk and simply paying Emerald Airlines a fixed fee for the non-PSO Dublin routes, while Emerald is operating the Belfast routes on a fully commercial basis and simply paying Aer Lingus for the name/booking engine.