Alex Woodward wrote:
Are there any water lilies that would be ok to plant at a depth of 80 cm in
the UK, or is this far to deep?

AFAIK, water lilies *are* deep-water plants (ie. by small-pond
standards), and 80cm should be right in their range (except possibly for
some dwarf varieties). Just go look at any natural marsh: as the ground
slopes off you get the boggy plants, then small emergents like
pickerelweed and arrowhead, then cattails, then lilies in the open water
that's too deep for the others. The leaf stems are easily a meter long.

-- Kizhe