2005 C5 trailing arm bush

[GB]

I need to replace the N/S trailing arm bush - the front suspension is making a loud noise when driving over potholes, there is quite a bit of play (I can feel it through the steering wheel when braking), plus there is a MOT advisory about it being quite worn (115K miles).

Is the bush easy to replace, or is it easier to replace the track control arm (plus ball joint)? Looking at the pictures I presume the bush is included/already attached to the arm.

I see Lemforder are most expensive, are the other brands (Ocap and Qdrive) worthwhile?