Thanks for that. Pinged it - 4 packets sent 4 received. Did the "flushdns", Nothing.
Whereas my wife's computer would connect to pprune, the links (eg to this forum) would not work.
Eventually (and I fear here lies the answer somewhere) I replaced my recently installed D-Link router with the Wanadoo/Orange/France Telecom Livebox and here I am, all three computers getting pprune with no problems!
Oh dear!