Hi Macingosh,
Thanks for your help and advice. it's been a great help.
As soon as I deleted the cookies, some of them were back within 10 secs i.e. Doubleclick, Mirror Football, etc. The one from Mirror Football was surprising, as I have not visited their since last May and the cache has been emptied. I hope they haven't bugged me.
It seems that nearly all websites visited leave some kind of tracking device in your cache, so they can constantly track your movements. I think emptying the cache is next on the agenda.
Thanks again.
Mac-Ho,
The update I downloaded was either late Friday night or Saturday just gone and it appears that the format has changed. As has been suggested it may be a 'Lion' update or a 'Safari 5'. I'm unsure at present.