There were two lanes in my direction, leading up to a traffic light. This was red, so the cars in the right lane weren't moving. I was in the left lane, with the parked car (a Land Rover). The door hit me in my ear, then kept swinging out and knocked the bag off the front of my Brompton. I wound up sitting on the bonnet of the car next to me (a Ford), while my bag was on the ground in front of it. I'm glad the traffic light was red, though; if it had been green, I probably would have wound up underneath a car instead.
The Land Rover driver asked me whether I was ok, and I said no. Although I had my helmet on, I don't think it really helped, since it doesn't cover my ears. The Ford driver was very supportive, saying that it was entirely the other driver's fault for not looking before he opened the door. Considering that he was minding his own business and then wound up with me on top of his car, I think this was quite generous.
I asked the Land Rover driver for his insurance details, but he refused, and said that I could report him to the police if I wanted to. The Ford driver noticed a scratch in the side of his bonnet, so he wanted the insurance details too. I've swapped contact details with the Ford driver, and we've both written down the licence plate of the Land Rover, so we're going to report this to the police; if they get two separate reports with the same information, hopefully they'll take it seriously. As for the Land Rover driver, if he doesn't go to the police within 24 hours then he's committing a criminal offence ("failure to stop" and/or "failure to report"). As I understand it, this still applies even if he was completely blameless by opening the door. (There's some info about the legal aspects here.)
My bike didn't seem to be damaged, but the front pannier was. The bike has a block on the front, and the pannier has a corresponding socket, so you can basically drop it into place. When the door hit the pannier, it shattered the socket. I don't know whether the socket can be replaced on its own; if not, I'll have to replace the entire pannier. After the collision, I pushed my bike round the corner to the station. I have a shoulder strap for it, so I used that when I got to Croydon, basically slinging the bag across my back like a satchel. It's not ideal, but ok for short hops on quiet roads. I'll swap to my other bike for a while, and I won't use the Brompton pannier again until I get it repaired.
As for me, I'm still in one piece. I ran through the first aid checklist for a head injury: no blurred/double vision, I could remember the collision, and I knew where/when I was. At the same time, I was aware that if I did have any memory problems then I might be missing out a few steps!
Tuesday is the SJA class night at my local unit. I considered skipping it and going home, but I thought that being under observation by a room full of first aiders was probably the safer bet. This also meant that one of my colleagues could do some extra checks for me, e.g. testing that my pupils were equal and reactive. I put my hand over my ear after the collision, and I noticed that there was some blood on it. Fortunately, this turned out to just be a small scratch, and he (colleague) said that there was no blood in the actual ear canal. I felt quite subdued after the incident, and he said that I looked a bit shaky. I changed into warmer clothes (long sleeved shirt and jeans rather than T-shirt and shorts), which helped, and by the time I left I was pretty much back to normal. My ear and jaw still ache a bit, but I'm sure that will pass.
So, tomorrow morning I'm off to the police station to report this. The last time I got hit by a car (in February) I submitted the details to the RoadSafe London website as a near miss. However, they said that since it involved an actual collision I would need to report that at a police station. So, I'll mention that at the same time, although it may be too late to do anything about that now.
After my previous collision, I said that I was going to get a helmet cam. I haven't actually done anything about it since, but today's event makes it more of a priority. I also need to be a bit more paranoid about parked cars. Ideally I would always stay 1 metre away, so that I'm out of door range. The trade-off is that I may need to leave the cycle/bus lane to achieve that, so I'll be at greater risk from moving vehicles in the other lane, but on balance it's probably worth it.
Edit: I've been to the police station and filled in a collision report form (which took about 45 minutes!), so I'll see what happens next. A colleague also pointed out another danger of parked vehicles: White Van Man might swing open the rear door as you cycle past. So, even if you can see that the seats are empty, don't get too close.