I second this, 2.5-3 hours between flights at a minimum. By the time you get off the aircraft (you may decide to wait until all other pax have disembarked), clear security/immigration as appropriate, visit the baby changing room one or more timed, feed or whatever, you will not even have an opportunity to think about a sandwich or coffee for yourself before having to find the next gate.

I am not sure if it is a BA policy or practice (if it is, it’s very good) that, load permitting, the adjacent seat on short haul is blocked off. From memory, out of 5 flights on A320 series, we had a row of 3 seats to ourselves (2 adults and 1 lap infant). Could have been coincidence? In any event the extra space makes a big difference, and most other pax would in any event rather avoid sitting in the same row as a baby if load permits.

All the best of luck for flying with triplets!