T2 flight connection centre is usually a breeze. I’ve never had a queue for security there, though they have a tensa-maze ready on standby so maybe there are some busy times. After security you will need to go up stairs and clear biometrics and the U.K. border but again there are rarely significant queues. Aer Lingus leaves from gates 21-23 ish in T2A so it’s just a short walk across the main area from the Border to the gate (think half the length of T5A). Should be very doable if all on time.