Got a response from BA (without much fighting) to say that it is only BA operated flights that were eligible for the full tier points etc., BUT as a gesture of goodwill they will give them to me anyway.
How lucky am I?! /sarcasm.
Full text below.
Thank you for contacting us about your flights with Iberia on 28 and 29 May 2015.
I am sorry you were disappointed your flights were credited with less Avios and Tier Points than you were expecting.
If you booked a BA flight before 28 April 2015 and the flight date is on or after 28 April 2015, we will credit your account with the Avios and Tier Points you would have earned before 28 April 2015. Unfortunately, our agreements with our partner airlines state we should only credit partner flights based on the awarding rates at the time you flew.
However, as you have been misadvised about this, I have now credited your flights based on the awarding rate at the time you booked as a gesture of goodwill. I have made a manual adjustment to correct the amount you've earned, which you can see if you log in to your account at ba.com.
I hope this is a solution you feel happy with and thank you for choosing British Airways.