@jekkyl cheers for the offer of your unused tank, but I’m a good few miles away in Sussex.
My existing water butts are 2’ in diameter, with about 3’ total distance between shed and fence. This doesn’t leave enough space for IBC’s etc, however I’ve seen several “cheap” single-skinned fuel tanks that would fit and provide 1000l + storage.
If I got a 2nd hand tank is there anyway to clean it of fuel residue, so as not to kill the plants nor make the garden smell like a station forecourt?