Thanks, J52 I've had a look at Primula capitata mooreana and so far it's the closest match. There is no stem at all though at the moment, let alone a tall one. I haven't grown lollipop primulas in the past because our soil is very dry and they tend to prefer a moist environment.
Thanks for all your replies. I haven't a clue how it got here but it's so pretty I will nurture it and hopefully be able to propagate some more.
More photos will follow if there are any interesting changes.