I've done one. It depends if the bolt that runs through has rusted into the sleeve.
If that has happened you will need a bi-metal hacksaw blade pack (£4) B&Q and a reciprocating saw (£29) argos
You will then cut though the bolt on both sides to free the radius arm and you can drift the innards out with a big hammer.
Shop 4 parts sell the bolt and bearing races for about £28.
If the rusting hasn't happened it's an easy job.
These are the same/very very similar to those on the Fiat Punto of which I have done 2. I've posted a guide on the Fiat Forum website as how to do it. It's not difficult, just make sure plenty of grease is pushed into the cavities and bearings. I obtained the kits for about £10 each from Desira.
Standard tools required, a suitable drift and a big hammer (and some care pressing new races into place). I did it at home.