Thanks Maggi.
I had seen that, but I am always cautious taking comments like that at face value. All too frequently, the person commenting is in Thailand, Florida, The Philipines, or somesuch (warm or very warm) place. It does cite some interesting "facts" about stress and flowering though (all I need to do is get them actively growing first...).
I haven't checked in the case of Eucharis, but have stumbled upon almost countless YouTube videos covering Adenium cultivation that fall into this category, not applicable to the UK.