There may have been some immature corms of darker forms such as Whitewell Purple among the original planting, and these have only just got to flowering size. One of the delights of 'Tommies' are that if you have a few different cultivars to start with, the bees will give some lovely new variants. Put in some 'Bobbo' and 'Pictus' and you will have a lot of variation to choose from.