Tim Lamb wrote:

snipped
IBC containers of my experience had wooden supporting pallets built into
the frame. Convenience for handling as they are intended for multi-trip
use. These rot readily on contact with garden soil. Current construction
may have moved to plastic.

Large cylindrical plastic barrels used for shipping Orange juice etc.
may be available.

Are you near to any Dairy Farms? At this time of the year, silage
making time, Dairy Farmers use silage acids to aid fermentation in the
silage crop. This acid comes in large 60 gallon plastic barrells that
are ideal for storage of water once washed out.
I used to have three of them.
Wash them out, fit them with taps and away you go. Usually free as
farmers are pleased to get rid of them.
Petefj