Hi Tim
There is a small space either side, between the trunnion and the vertical link containing the flanges of the plastic bush and the thin tinplate dustshields. Hacksaw through the bolt either side of the trunnion through these. This allows you to separate the trunnion from the link and gives access to the rest of the bush inside the trunnion. Then you can remove the bush by a combination of melting, drilling and/or pressing. New bolts and bushes will obviously be required for reassembly!
The new bush kit looks like this
http://www.classicpartstrader.com/tr...-kit-758-p.asp
regards
Andrew