Now I had said things were easy to apply in another thread but I don't know where to start with that one! Should the ignore list be stored on a cookie, a list in membership or what?

The only think I do know is that something like OE even will allow blocking of an individual. I have tried it (Ghost 1999 on rmc being one example) but found the missing posts caused me more trouble than they were worth. I think it much simpler to ignore who you may consider a prick but to have the reference to look back if someone responds than to try to play your own game of filling in the gaps. Others may differ of course but I think this one presents the oppertunity of filling in gaps to say what one think a person states rather than reading what they did say (and sometimes, even the person you dislike can make a point you agree with and the person you like not).