Thanks for the feedback, to everyone!
I eventually bought second hand gear. After much research I chose to go for a Dedicated Micros solution.
I bought a BX2, since it does everything I consider that I need and then some! It is a reconditioned unit, but for the bargain price of £300 even if it only lasts for a year or two I will be happy. I got some second hand Sanyo cameras, the guy I bought them from was very kind, he helped me out snce I'm starting a new business on a very tight (almost nothing) shoe string budget. When I get more flush with beer tokens I will buy more cameras from him and give him some proper money. I've also offered to build a computer for him at cost - which will be nice for him since he's into serious kit for his gaming.
I got a Vista housing, very nice, but unfortunately I might not be able to use it - long story about space reequirements vs glass.
Once again, thanks to all for your help.
Nick