"Stewart Robert Hinsley" wrote...
This plant was labelled with what I assume was a cultivar name - 'Gill
Lewis' - but didn't have any indication of what genus or species it
belonged to.

http://www.stewart.hinsley.me.uk/Images/GillLewis.jpg

Does anyone recognise it?

I'd like to have seen the leaves but...

Achimenes sp. possibly grandiflora.

If so the roots will look like long thin maggots!
--
Regards
Bob Hobden