yup, but it was only for basic training, no real gucci kit there!
certainly no space for spares!
I figured out what I had in there a while back.
remembering that you had a lot of Personal admin gear on the 58" webbing (wash kit, boot kit, first aid, rations etc)
for basic training in the large pack we had:
spare combats, pair of plimsolls, woolly hat, issue woolly gloves(if not in pocket).
spare mess tin, spare rations, waterproofs (DPM PU coated type), and the top of the padded insulated suit, not much else.
we had to carry either a shovel or pickaxe as mentioned before.
the modern issue sleeping bag/bivibag combo would not have fitted.
the earlier weeks training you didn't have the webbing, just the large pack! without a yoke to clip it on!
I never saw the issue of PLCE(unless self bought), or Goretex, though we had S10 respirators, and SA80's were just coming in.