Lovely thread!
I personally made up several of the Immersion suit pocket bags (See Tash's post) whilst on the Worlds oldest fixed wing squadron, seem to remember these fitted quite well on the Jag cockpit coaming!
Whilst I was acting as EA for SE at Strike, I recall an SEM proposal coming in, to fit a small pocket on the back of the cape leather gloves ("If Carlsburg did flying gloves..etc...") The idea was for UTPs carrying out post maintenance test flights of Jet Provosts to collect up and store pieces of 'locking wire and debris' that 'inevitably' accumulated in the canopy during the inverted part of the test!!!
II don't think they were big enough to hold a chinagraph......
(As an aside, , I suspect the gloves black market trading value was reduced if the pocket was fitted😋