I agree with Nick, the last item is a rocker cover. It is certainly very similar to one off a Cheetah. I have always found numbers on Cheetah rocker covers.

I do apologise Ericmonk as Alan clark states yes it is certainly a rocker cover for a siddeley Cheetah engine,( in the same box of relics was a Cheetah engine engine plate)

Also im now thinking the plate with Air Filler Brakes/ Air Filler Gun are from an Anson as exactly the same disign as a couple of other Anson plates i have.

Thanks again..