I've just replaced my o/s suspension leg, does this mean I will need my tracking done? It was done back in january 2011 after I put four new tyres on my car...

if you put the track rod end the same way as it was (or released the balljoint) all you have to do is check exactly how the steering wheel is positioned under driving.

also, gently let go of the steering wheel under driving and check if the car wants to go to the right or left; if it doesn't do any of that the tracking will be ok, if not it's well worth doing it again or your new tyres won't last as long as you hope