Bit rushed this morning, but here's a couple of pics of my set up. Note I chose the smallest diameter pin remover that fits inside the outer collar. Then give it some taps with the wee hammer (shown). This can only be done from one side. I uploaded this pic in larger format if you need to zoom.
To refit, simply put the pin back in, put in the collar from the other side and push together. You can clearly see that the pin is in 2 parts on my last pic. This requires a bit of force and 2 flat objects (a protected table edge and the flat of a knife worked for me).
All tools were from a cheapie Amazon kit - nothing fancy.
Hope that helps someone.