Thank you both for your replies. Today's rain has destroyed the flower - so no chance of close up photos for now. I have several plants, so perhaps another one will flower - although I wasn't really expecting any flowers till next year. Do they usually flower in their second summer?
I did take a pic from a different angle, but the colour did not show up well - the photo is too pale. The lower petal (or whatever the botanical term is for it in roscoeas) looks much larger than other roscoeas which I grow. In the photo, the rain has already damaged the fragile lower petal. Sorry, not a brilliant photo - taken with my new tablet.