Does this help ...
https://www.britishairways.com/asset...nal-5_intl.pdf
it is impossible to say what gates you will arrive at or leave from
You will likely arrive at T5A
Assuning you do ....
15 minutes from leaving the aircraft to clearing security (assuming Dublin arrivals need to go through security at flight connections, connecting from a domestic flight does not. Otherwise its 5 minutes from leaving the aircraft to being in 5A departures
New York flight will probably leave from T5B or C (but may leave from A)
Assuming it is then you are up to 10 minutes to get onto a train and across to the other terminal
If your inbound flight is on time 65 minutes is plenty of time. MCT is 60 minutes,