Airprox or CHIRP?????????
Genghis,
I feel for you, you've obviously had a scare and fortunately, you've lived to tell the tale. In the air, there is never enough time or information to make the correct decision, one has to do the best one can with limited information and based on one's experience. 50-50 hindsight is all very well, but it has the advantage of more time, more information and less distraction - one is not trying to fly at the same time!
I believe you were correct not to go-around. In cases such as this, I believe it's best to stay predictable and keep doing what you said you would do. After all, what would have happened if you started a go-around and just as you did so, G-HIM did the same.......
Your incident deserves all the publicity it can get. File both an Airprox and a CHIRP. The latter will reach all GA pilot's eventually and the former will get to a wider audience.
Finally, be aware that the Airprox system does not allocate blame. All it does is analyse, report and publicise - which should help prevent the same incident from having a more catastrophic ending next time. Keep your tape - I'm sure you have anyway - it'll provide good evidence.
A