It would be good to get that one nailed because the worst case scenario is that Jeremy didn’t call his dad back for over 16 minutes ( not that he ever actually did, of course)
A while ago, I tracked down a telephone engineer who worked on the same type of exchanges and the one in Maldon.
This is what he said - just to add that the Maldon exchange wasn't maned 24/7 so there was no one to physically end the call or apply the howler.
"Right here is the info on Maldon which looks to be a small exchange.
In 1980 it was a Strowger electromechanical exchange with 1098 business
lines and 4170 Residential lines. That old Strowger didn't have
automatic lock-out or parking. Just a lamp to show the engineer that a
line hadn't replaced the phone. He may or may not have bothered to look
at it. They didn't bother with a solitary one, only if there was a lot,
showing a cable fault. He could have applied a howler to the line from
a test set, no indication of how long it had been off-the-hook. The
later ones before system X didn't have logging of events, and they
wouldn't have bothered to record it for some legal reason, not knowing
about the possibility."