Yes there was one point where every single through platform was blocked, as platforms 1, 2, 3 and 8 were blocked due to abandoned GTR trains, 4 had a GA train that was meant to terminate in platform 2/3 and another GA train terminated from the north in platform 7 (booked 8). This delayed a few trains by quite a bit and the signaller probably didn't want that to happen again
It’s very standard fare these days by signallers; they’re acutely aware of the risk of stranded trains (as many TOCs are too) and only will start to signal trains once things are confirmed to depart. This relies on good (or at least acceptable) comms between signallers / NR control / TOC control. Where things like this happen, there tend to be issues with this and/or trust in service recovery from one party at least.
Some really wouldn’t believe me. I personally couldn’t be like that but I know so many that couldn’t care less.
You have to remember that such moves are not always quick and if no safe walking route back can take a very long time. It all depends on the location.
Trains should still not be left on a running line without a driver if stranding other trains and blocking forward movement. Of course this might be a relieving point but still almost every driver has the decency to a) remain with stock or b) terminate and ECS somewhere appropriate. Of course there’s lots of ifs and buts and caveats with option b) regarding diagramming / stabling points / crew availability and awareness but it will certainly get pushed into high priority if no available driver at a through location.