i believe the record stood at 60 for some time.
That was a fun hour. 28 arrivals and 32 departures IIRC.
Adding the second runway did not bring forth as many advantages in moving aircraft as you would imagine. Nearly all departures from 24L followed the same initial route (due noise abatement) and so there was little use made of the "Manchester minute" which for some reason had to be 60 seconds. The "Manchester 2 minutes" was used a lot though, and it, unsurprisingly had to be 120 seconds. 117 seconds was apparently not enough.
