DIY valve guide replacement?

[S.G.Adderson@ukc.ac.uk]

The Haynes manual for my Mini says to remove valve guides by drifting
them out using a suitable steel punch but doesn't say how they are 
replaced.

I would have thought that they were simply pressed in from the combustion
chamber end, seeing as the tops are chamfered. Has anyone had any 
experience of either removing or replacing them?  I have access to a fly
press (whatever that is) or a large printers hand press but don't know if
either would be up to the job.


Steve