When a BA flight was cancelled recently from DUB to LHR, I rang up the BAEC and specifically asked to be out on the next Aer Lingus flight out. All done very efficiently and effectively to award 20 points in Y. Despite not being in OneWorld, I received an apology from the Aer Lingus Business checking desk for being placed down the back (I was just glad to be in the flight).

Also received 10 points (N code) flying from Cardiff with Aer Lingus, booked as a BA codeshare.

It seems that the BA codeshares with Aer Lingus are more expensive than the Aer Lingus fares.