well for cams events it must be able to be reached by the driver WITH seatbelt or harness on. so either under drivers seat, or passenger seat, or somewhere around the centre console is pretty much the only place.
I haven't used the chubb ones but they have a pretty good rep.
the BFI ones are good. I've used them and I've used some other lame-o ones (can't remember brand) and they were rubbish.
doodz, the one you want is BFI Dry Chemical Powder (ABE) Extinguishers.
This is it: http://www.firstaidsales.com.au/component/...emart/Itemid,1/
compare it's rating to the one you have. the BFI 1kg one is 1A,20B:E and again you must have an all metal bracket (the BFI one comes with it).