Yes, R is right. Pure Sturmey Archer, but don't think you can just buy another that looks the same and it will fit. Sturmey Archer would willingly change the main shaft length and shuffle the clutch arrangements around for any bulk purchaser.
Luckily for us they cheerfully listed all this in their parts lists so you know exactly what you are after. Of course this can entail getting several copies of their parts lists but most are available at the VMCC library and many a dismal winter's evening can pass by trawling through them. Ask me how I know.
You'll be amazed at how many ways S/A could ring the changes to suit a buyer.
Cheers,