What tyres do you have ? What pressures do you have in the tyres ?
Rear bushes can be easily checked for wear but do not mention that you suspect anything to the garage or quick fit fitter just to avoid wool over eyes syndrome..
Rear bush wear can normally be heard with a distinct metallic "clonk" if you travel over a small kerb pothole etc etc etc..
Another thing to consider is the condition of the road surface..
Without wishing to sound patronising currently roads are pretty greasy and still have a coating of salt / grit from the recent cold snap..