If you do not get an interview for Flight Deck there is a 'back door' opportunity advertised on the Aer Lingus website
Aer Lingus: About Us - Aircraft Cleaners
I understand that modular candidates will have a head start as they are more likely to have had experience cleaning bars etc around Dublin. However CTC Cadet candidates will not be discriminated against . Aer Lingus expects to create a holding pool for cleaners as they are likley to be overwhelmed with candidates for these 'exciting positions' which offer 'full airline benefits'
When you apply you will receive an email which states "...Aer Lingus will be in contact in the near future with those who best meet our criteria..."
Note that the training offered is the Airbus 'Tech Stop Operational Support Executive' which is only delivered in Toulouse. Only candidates who pass the theory exams with a mark of 85% or more and passes the 'Lavatorial Test' in the first series will be accepted. Aer Lingus regrets that if the candidate fails these tests, no altrentive employment will be offered