After three years of DIY, first with a trailer and 400l, and then with a van, yesterday i took the plunge and had my first proper professional tank instalation.
The features are.
Two roof mounted, electrically driven cox reels exiting the side doors.
An on demand hot system
800 litre skid mounted tank
A back to tank bypass on each reel feed (the benefits are i can take pressure out of hose system at night, i can fix and diagnose problems without turning on pole taps, i can defreeze frozen reels in morning by repeated shunting hot water in and then depressuring) So two ports on the top of the tank take these tapped bypass'.
Two tapped outlets on the bottom of the tank.One outlet feeds two operators, but the second outlet allows for a third operator should this arise.
My conclusion is I should have bought a pro system three years ago.