Many thanks for both your replies.
I have since identified the plant to be dubious, and have since posting, unearthed it. Much as I adore such beautiful flowers, I can not take the risk of not knowing 100% certainty.
In our family mansion we have a large Victorian conservatory. In it among other exotics I grow bourganvillia, and have a large kumquat plant whose fruit is utterly delicious. Especially when preserved in gin and sugar syrup, the preserving jars lined inside with kiwi fruit. And deffy not for children!