Well done Eric! No wonder it had us stumped on the forum
That plant is also known as Eustoma grandiflorum. I have it (and the two others below) in the Master Database and when I click the RHS button, I find it was last listed in 2008, so it was available in the UK up to that date.
Chiltern Seeds sell Eustoma russellianum, F1 hybrid, 'Echo Series' 'Echo' Formula Mixed
http://www.chilternseeds.co.uk/chilternseeds/321142/moreinfo/pid/31510619Synonym: Lisianthus
This is a splendid range of flowers specially bred for growing in pots or for the production of luxury, long-lasting cut flowers. A double-flowered variety, it produces blooms about 3¼ ins. across, velvet-like in texture with lots of lovely petals and something everyone will be talking about! A wonderful cut flower, a bunch of which will go a long way to settle any argument! The formula mix is made up of several separate colours including blue picotee, pink picotee, yellow and pure white. 2½ ft.
and also another variety, Eustoma russellianum, F1 hybrid, 'Heidi Series', 'Heidi' Formula Mixed.
http://www.chilternseeds.co.uk/chilternseeds/321142/moreinfo/pid/31510616Superseding the 'Yodel Series' we have offered previously, this is another splendid new range of flowers specially bred for growing in pots or for the production of luxury, long-lasting cut flowers. As the bloom develops, it starts like a Rose, passes through a Tulip-like phase and at the end transforms into a Poppy. Definitely a flower for Superseding the ?Yodel Series? we have offered previously, this is another splendid new range of flowers specially bred for growing in pots or for the production of luxury, long-lasting cut flowers. As the bloom develops, it starts like a Rose, passes through a Tulip-like phase and at the end transforms into a Poppy. Definitely a flower for birthdays and other not-to-be-forgotten anniversaries. The formula mix is made up of several separate colours, all very lovely, including salmon, pink picotee, deep blue, wine red, rich champagne and yellow. 2-2½ ft.
I think Eustoma russellianum is a synonym of Eustoma grandiflorum