James and John,
Thanks for your comments.
I have windows on my laptop, have to I'm afraid because of some software that is used by a group of which I am a member. But I do have a Linux box running Ubuntu, so perhaps I would do better using that, at least for the sys administration thing before I get onto my web work.
Can't for the life of me think why I set the execute permissions - I put it down to age.
Yes I do think it is a problem with the keys as everything else is set up properly, barring any silly typo type errors. One of which I did discover was naming the file authorised_keys (English rather than American spelling) but I discovered that early on.
It is frustrating as it is a simple procedure so it must be a simple error'