DD used a plastic bowl for all meals, and a cup with a marker on it for measuring how much water was needed to make her Quaker Oat Breakfast thingies.
She had a very light tiny but warm sleeping bag, and a fab Coleman Epsilon 2 Tent that her friends laughed at (for being so tiny) until they compared its size & weight to theirs. TBH, doing it again we would buy the 3man for 2 to share as the 2 man was REALLY tiny, but incredibly watertight & lightweight. In pairs, one carried the tent, the other the Trangia (supplied by the school)
Get Goretex boots. We couldn't afford Goretex jacket & trousers but we got another very waterproof sort - think it was Berghaus Aquafoil, and it worked. Swindon Outlet Centre was useful - and use your DofE discount cards.
She needed Gaiters for a few trips, and warm hat & gloves.
She wore walking boots all day & had a pair of flipflops for the camp (smallest & lightest). We bought a microfibre towel and cut it into quarters, a quarter was enough for a trip.
Small first aid kit, torch, compass, hat (good for rain or sun).
The girls braided their hair so it didn't need doing whilst away.