@dhaslam - that's some good info you have there, assume you have some kind of home weather station system ? Wish I had such a steady spread of rainfall, it would make things so much easier ! I think I had two decent falls of rain between May and Jul, both very heavy and overwhelmed the guttering I have at present. The rest of the time any rainfall barely damped down the roof tiles, let alone anything enough to bother the tanks

Respect to you guys with the massive cisterns - more than a little envious there. Trying to picture 100 IBC's in my back garden... not sure I'd have the space somehow...
@Amy - If you're waiting for summer to start you must be the opposite end of the world to me? Re: the spelling / technical pendants, I was a little worried whether litres should be l or L... However since my discovery of Claude Émile Jean-Baptiste Litre, I'm happy to use L

I will also check out that book, thank you !
Back to the rain tho, since my rant on Sunday it hasn't stopped raining since... tanks are full and I'm back to planning the installation of the next IBC, it will sit on top of the existing one, so I'm currently looking at pumps, float switches, relays, battery and solar charger, and of course all the plumbing to go with it. Confession - had to top up the existing tanks from mains twice over this summer... and that really grates !