The plant you describe, Spathiphyllum floribundum, was sold by
the now-defunct nursery Anmore Exotics (now Wyld Court
Rainforest - a private tropical plant collection) at Hamstead
Norreys, near Reading in Berkshire, UK.
Spathiphyllum floribundum periodically appears in the trade in the
UK but is not anywhere so easy to grow as the 'wallisii/Mauna Loa'
types and thus seldom remains in cult. for long.
Two other species are available (sorry if you've got these and have
said so, Toby, I've not been following all of this discussion):
Sainsbury Homebase (for the benefit of US aroid-l folks this is a
chain D.I.Y. supermarket here in the UK) is selling S.
coclearispathum at some of its outlets for 20 quid or so and several
aquarist stores are selling Spathiphyllum cannifolium or S.
commutatum (probably the latter) as a fishtank decorative under
the name 'Kelantan Sword'. Next time you're at Kew, Toby, take a
look the spathiphyllums in the Victoria Tank in the Princess of
Wales Conservatory, they are plants I got as 'Kelantan Sword' from
an aquarist near Heathrow.
Royal Botanic Gardens, Kew
Tel. (+44) (0)181 332 5207 ((+ 44) 208 332 5207 from June 1999)
fax. (+44) (0)208 332 5278 ((+44) 208 332 5207 from June 1999)
email: firstname.lastname@example.org (work)