Just write to the JPA in Glasgow asking for the docs. They have to provide BUT it took nearly a year for me to receive mine. Their stated reason for the not -so-prompt reply was ' very busy' . 'fraid it is a case of ' Wait out'
Some time ago I obtained my late uncle's medical records (he managed to be invalided TWICE, 1937 and again in 1940). There was no reference to any incident of his having been knocked unconscious, which family lore says caused him to be hospitalised during his training. Leads me to suspect that records may be discreetly edited to avoid Army/MoD embarassment, although of course muddled filing may contribute as people had other things to worry about in 1940. When I sent for my own personnel records one letter which was missing was my own one asking for PVR! of which I had kept a carbon. Still well worth sending for the records of deceased forebears though, although there is a long wait; it is surprising what one can learn about them.