@Graham .....sorry, perhaps your assumtion is correct !
Perhaps really a bletilla. Compared to my other bletillas (formosana, striata, ochracea, sinensis) the leaves are at least 2 - 3 times wider, also the plant is bigger. To systematics I unfortunately found many different information, but perhaps it could be a foliosa? Can not find a description in the net :-(
Greetings
Bernd