KMXC560 how to replace small pully & tension bar?

I have to replace the small pully and tension pin on my Kenwood Chef KMC560 I tried to use the liquidiser when not fully engaged. I stupidly tried to force the liquidiser into place before turning the mixer off and pushing down on the liquidiser I have ruined the small pully. How can I get the old one out to replace it? Many thanks.