Rear Wishbone

Friend of mine is checking over car for me and says there is play in nearside top wishbone.Are bushes something that can be changed on its own or should both sides be done together. Any help would be greatly appreciated regarding this.

How much play is there? with the standard rubber bushes they can move a couple of mm anyway.
Like for like changing then you can just replace one side only, a better alternative is the Eliseparts nylatron bushes

Not sure phil but he says the movement is from back to front. Also there is a wrattle from the nearside on lefthand corners. (hope this makes sense, as you might have guessed I am not the mechanical minded sort)