Hi Sarah, you OK. I'm in the UK too, England. Basically, Yes, it's expensive but you can use bottled water, Evian or something. Where are you, anywhere near me. I have a 50 Gallon RO water Butt and would be happy to give you as much as you needed. I also have 7-8 25Litre water cannisters hanging around from when I moved house.
Brucey