[WestKent5097]

Not forgeting the Guards, SAS, SBS, Royal Engineers, Harrier ground support, Naval gunfire support, Gazelle helicopters for spotting and Sea Kings and a Chinook for lifting supplies and artillery.
As already stated I think there was about 1 troop of Scorpions/Scimitars in the later stages. But basically it was an infantry force of around 2-3 Brigades in size.
There may have been a few of the Royal Marine BV series of vehicles and possibly a few CET, but I'm not sure on that.

Argentines were similar, mainly conscripts and marines, but had a few armoured cars which only operated around Port Stanley and some AA guns, a Roland SAM and some air support from Stanley and possibly the mainland. Also a few helicopters.

There is a scenario in the game which may give you some idea and there is also a Goose Green scenario available on a couple of sites (wargamers depot is one I can remember). One of these puts you in charge of "2 Para" so it should give you some idea of how much infantry you want to control at one time.