Charlie Time,
"There are no 'extra' Wildcats as far as I'm aware."
Time to be a little more aware mate, there are four additional Wildcats, to go to SF as LUH, thought to be for 657 Sqn, along with four that were originally destined for the Army in the original role. So it's now 28 for the RN, 30 for the Army and 8 for SF, hence four extra Wildcats.