Just for future reference for anyone else asking the OP's quite specific question: I can find that information, root and branch, about gate timings, opening, closing, IDAHO displays, but only for the first 48 hours or so. It then gets archived off and I won't have a justification to get that information back. An 8 person offload is at the top end, but as you saw, BA will cheerfully do it, particularly if HBO, it's just 2 buttons on the screen.

On residual data, BA322 LHR-CDG pulled off gate B46 at 20:07, on scheduled departure at 20:05, with the captain requesting the pull at 20:06, so smack on time. A319 took off at 20:26, so it had a quick departure by LHR standards. Reached Roissy at 22:08 and got to a gate at 2C for 22:15, which is fast, but not so much at that quiet time. Scheduled arrival time was 22:25 CET. On the face of it, this was an on time departure and I can't see any mitigating factors why not to be at the gate on time.

Welcome to Flyertalk and welcome to the BA forum Smith23481. There is usually an expert online at the time, so don't hesitate to use this forum in and of the moment. The one message I will reiterate is that gates can close at 20 minutes to departure, and unless you have 101% knowledge of what is going on, you need to be at that gate at T-21. In reality it is often a bit later, but that is the Service Level to which staff are held. BA is no different to many other airlines in that respect, the USA based carriers are much harsher about this (and often with 30 or 40 minute cut offs).