Levering under the lip of the bushing at its surface mounting point with a screw driver might work if the bushings are not rusted... but for me they were pretty stuck fast.
I used bolt cutters to snip the sides of the metal casing in the bushing and simultaneously trying to lever them out.
A sort of snip and twist motion got me enough space between the lip of the bushing and the sub-frame to get in screwdrivers and eventually a claw hammer.
With a claw hammer in place I could pull the bushing out just that little bit further to fit in the thicker claw of my crow bar.
The bushing popped out. Nice and easy eh?
Has anyone got a better way of doing this?