Sacha wrote in :

Dig a hole! But I'd invest in some proper pond liner as ordinary
polythene will be far too easily punctured. Look in tips and
re-cycling places for old baths & basins, block the plughole and sink
the bath or basin into the ground. If you want to be designer-y and
are clever at such things, don't sink the bath but add a standpipe with
tap at one end of it and fit a recirculating pump so your bath is
always being 'filled'!

Thanks... One thing I'd really like to know, is whether the pond is best
sited in sunshine or in shadow, or what. I suspect frogs have a preference,
and I suspect that the amount of sunlight may have some affect on the
underwater vegetation, which may or may not be critical to the frogs'
wellbeing...

Can anyone provide insight?

Al