Rear Castor Bar, Bolt Replacement

[Seano350GT]

Ok so i need to replace the bolt in my front left, rear castor bar (behind the disk brakes) and it's basically impossible to do it from home as the original bolt is extremely tight and there isn't enough room to get a good go at it from being jacked up.

I need some advice as to who to go to to get this done,

Nissan have said "we don't have the equipment" the chick at the counter must have been drunk.

Pedders Suspension (Mackay) want $140 P/H and can't do it until next week sometime, although it should be roughly an hours work i still don't want to pay that much. I haven't tried anywhere else yet but i wanted to know if anyone has had this done before and could recommend a place or an individual to do it.

thanks