the answer, get a MErlin RO from ADWATS (andrew is on here) they work VERY FAST, so you could have it under your kitchen sink and fill your containers each night 
Matt,
One min your saying only get a RO unit for your needs then the next your saying get a Merlin RO unit that can produce 2700 litres per day.
Why have a RO unit that produces 700 L a day when you will only need 200 L ?? Comment taken from your website.
Abit confussing to the new comer?
Justin
Justin if you read his post, He doesnt have anywhere to store a Water Butt or container
So i thought the speed the Merlin put out water, he could fill his 6 or 8 barrels in the Kitchen while watching the news (or eastenders etc)
it has NOTHING to do with the amount of output, i was thinking of SPEED
it has to be cheaper than just DI