These are examples of 303 Auxiliary devices. The first one is the 303 cum .22 Parker-Hale as described on p.143 of Hoyem Vol.3 with the removable breech plug. The .22LR is interesting with the 2 small point crimps on the case. The second one is the 303 cum .22 Vickers with the off-centre chamber for rimfire so that the center fire pin of the Vickers will strike the rimfire of the 22 LR short. There is a logo on the base, but it is too faint to make out exactly what it is, but in all probability BSA, as well a patent number on the case, but again very faint.
The question is regarding the third one. It is too small for the 297/230 Morris and takes a 22LR Short, but only just. That would present a problem as the rimfire would not be struck by a centre-fire firing pin. There is an “EFD” on the shoulder of the adapter, but apart from that there are no other markings.