>>  p.s. I'll use this as a test to see if I can still post to the list 
> from my yahoo.com address too; I've not much hope it will :-(
> 
> Did @yahoo.co.uk receive the same ill advised changes? Not sure because 
> so far I don't see any bounce messages.
> 

Not as far as I'm aware; I just assumed anything affecting yahoo.com would also apply to yahoo.co.uk, especially as I've had issues on the NetBSD lists for years, but afaik that's down to some sort of plain text issue.