I believe connectorised means it has a pre-connected connector at the CBT end not the ONT end, are you saying the connector at the CBT end in the underground chamber was added manually as that would be strange.
I didn't see what went on in the chamber end. If what you describe is standard practice (i.e. the cable is pre-connectorised at one end only) then I expect you're right.
The drums of cable seemed pretty large to me.
I did see that the cable was pulled *towards* the ONT location, and it was not connectorised as it emerged at that end. So if it was pre-connectorised at the other end, the drum would have had to be completely unspooled and all the slack pulled through, before cutting. That could have happened - I only checked in occasionally to deliver cups of tea