Hi Anne,
That's pretty much how I was feeling over the whole Cadet/Junior/2501 things yesterday. Especially with the List 39 2501 image, appearing to show the pots in the junior format.
The star pattern #2455 was listed as a "new attraction" in the 1954 catalogue, only available in rosalin (it's on the same page they introduce the 2638 trinket set.) and listed in other colours; flint, green, amber, blue and pink, in List 39.
There are at least two other sets, 2652 and 2634, but unfortunately no pictures. I've attached an image from the June 1949 Pottery Gazette detailing the Sowerby stand at the BIF. However, the photograph of the stand shows the butterfly set.
I'm never too sure how the copyright thing works for snippets & adverts from old magazines, so if it needs removing I understand. It is an image taken from my magazine though. I also have a 1949 Sowerby advert showing the 2487 set, if you'd like a copy.