But I am blocked from this IP address, a PC not used by anyone else. This is the message I get when I try to edit:-

'Your user name or IP address has been blocked from editing.
You were blocked by Arwel Parry for the following reason (see our blocking policy): 
"Repeat attack on subject of article; surreptitious editing of external links to point at attack sites"
Your IP address is 83.138.136.90.'

I'm not even sure that that is my IP address.