I've collected some 1/48 Harriers for Falklands Conflict subjects. Airfix produced a 1/48 GR.3 and FRS.1, both out of production, but occasionally available from the usual auction sites for not unreasonable prices if you are lucky. Not the best of kits, with simple details and raised panel lines. There are plenty of accessories and decals easily available, so if you can find the base kit you'll be able to overcome the shortcomings.
Tamiya's Sea Harrier is widely available, but has some shape and fit issues from what I've read. I no personal experience of the kit.
Other than that you are 'kit bashing' like the guy in Harry's link, who has done an excellent job all round.
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Gareth
UNDERSTEER - is when you hit the wall with the front wing.
OVERSTEER - is when you hit the wall with the back wing.
HORSEPOWER - is how fast you hit the wall.
TORQUE - is how far you can take the wall with you.