BETD do a tool, which includes a bush, for 15 quid i think.
sounds expensive, but well worth it.
one of those things that would be a sod to bodge (using a suitable sized socket and a hammer), and risk knackering your shock;
having the tool for the job makes it take 2 mins, and easy peasy
the bush they supply isnt DU, its a plasticy thing, but they seem to last much longer and are cheaper. (2 quid each once youve got the tool?)
if you go down that route, DONT grease the bush when you put it in, the plastic absorbs it and it dies soon after.