This is considered the minimum required equipment, though as always is not a hard and fast rule:
DPM trousers or olive lightweight trousers
Ideally this should be an 80s pattern, 1960, 1968, 1985 but 94 temperate items, S95.
Jungle and windproof items are also acceptable.
DPM patrol cap, bush hat or artic cap, Navy Blue or Rifle Green beret.
MKIII, MKIV or MKV helmet (should ideally be netted and scrimmed).
MKVI Helmet (Must be scrimmed).
58 Pattern webbing is essential, anything modern will look totally out of place.
Any boots that offer ankle protection. Preferably black.
Period Correct -SLR, Sterling, M240/GPMG are all ideal but super expensive.
M16/M4 variants are acceptable, especially with carry handle attached. As always remove any optics and if you’re not sure it looks ok cover it in scrim.
G3s/FN FALs are a good ‘lookalike’ alternative if you already own one.
SA80 – check with organiser, sometimes they are considered too modern.