Just in case you weren't sure what the insects are, Royal Mail helpfully print Bees on the edge of the latest Concrete and Clay booklet. Concrete and Clay? That was a hit in the 1960s for Unit 4 Plus 2 which is the format of these books so it's what I might call them from time to time when the mood takes me.
The 1st reds are the now fairly familiar M15L MCIL coded stamps by Walsall. I do wish they'd credit the printers on booklets. The Bulletin just says ISP these days.
I don't think there's anything of particular interest about the definitives. The bee stamps, however, may be different to the usual sheet supplies as they have a design that overlaps the perforations, continuing just a millimetre or so into the background. As there is also a miniature sheet featuring all the set that is available too then it may be that that will have the same image printed with a similar extension. You may need to check but that hasn#'t got much to do with Machins which is what I am supposed to be writing about.
I would write more - if there were any to write about.