Hi,
I have been following these boards closely as I too have been issued with a red light camera offence notice. Unfortunately, the city of Mississauga issued me a court date in mid-Sept when I went to request a trial (no unreasonable delay there!). I also received the same form (5.1) as Naomi did and will be utilizing that defence prior to pleading.
However, I found an interesting ruling from the COURT OF APPEAL FOR ONTARIO regarding the admissibility of the photograph(s) as evidence (Waterloo (Regional Municipality) v. Yan, 2004 CanLII 32076 (ON C.A.)) which may assist some. The important sections of the ruling are 26-31. Essentially, the court ruled that the photograph "must" display the date, time and location of the offence either within the photograph itself or superimposed on it. The use of alpha-numeric values, without any means to interpret them, are not sufficient (32).
Looking at your photo naomi, it seems that while the date and time are listed on the top of the photo, the location is not (at least not intelligibly by a common person). There are also no street signs indicating the location of the offence (photo is a bit grainy so I may be wrong). Hence, the photo of your offence is inadmissibly (as the location of the photo cannot be sufficiently established) meaning there no longer is any evidence against you.
Personally, this ruling may not apply to me as one of the street signs is visible in the photographs of my offence (Airport Rd). So the photo places me at one street but not the other. I don't know if this appeals court ruling can work for me, but it will be part of a defence I mount.
Hope this was of some help. Best of luck.
Bee