T be honest 10 000 Avios is good going for such an issue. How long was the flight and could they give it to you subsequently or was it used. Might be worth having a word with CSM on boarding to see if special meal has been loaded before departure.

if you pursue this it will IMO be a waste of time as typically catering issues is of the 4000 Avios mark. Compensation of the tens of thousands is a thing of the past.