I cycle frequently in London.
The motorist was silly, impatient and several other things. Not good road behaviour at all.
The rider appeared to be making something of the type of incident that many move past and forget about. There are bigger wrongs out there.
I do not condone the actions of the driver, but stopping in front of him was not going to achieve any of the outcomes any sane person might have sought.
I filter up the offside a lot when in heavy London traffic, but I always make sure I clear off as soon as I have the room and do not allow my riding to give the impression that I might be 'holding anyone up'. The OP appears to have filtered, got back into traffic and then sauntered. There's no law against that, but you will get honked for doing it.
I am by no means a saintly cyclist in traffic, so I do not type this from the saddle of a moral high horse. I weave, I filter, I ride with 'verve' and I have sharper elbows than Abdu-thingummy. But I would not filter, push back in and then dawdle. To the motorist, the impending wait at the next traffic signal is not an issue here. Rightly or wrongly, he may simply see a bicycle push in front and then fail to keep up.
It may be that the driver will be prosecuted, but once triggered by the beeping, this whole situation was nurtured and fed by the OP.