Seb,
sorry to say I can't see your letter cutting any ice with the authorities.
Rush hour traffic in the City Centre is so bad you'd be unlikely to be going fast enough so that your braking would be likely to cause someone to rear-end you.
Also, the points been made that the red-light cameras do give a couple of seconds leeway before they snap you, so again I fear you're stuffed.
Still, I admire your never say die attitude, and I can't think your letter could do further harm. I guess there's even a slim chance of it working, but it's a very slim one. Certainly my letter didn't help when I got done for parking in a Loading Zone, but you dont know unless you try, so good luck!