I am now beyond confused, I installed SS on a test site and the Youtube Service worked fine, now I am duplicating this site for production and the Youtube service installs fine but when I go to Save and Publish a Youtube page I get 'Validation Failed'.

I even copied the old, working directory into my new site but still the same - I only created the original a couple of weeks ago.

I believe there is nothing outside of the youtubeservice folder to configure to get this working - am I right or have I missed something?

I am using the Blog module with both sites.

Validation Failed? Checked your date formatting? :D

I am really not sure what you mean here.

Can you explain further or point me to where I can get more info on this?

Well if the error is validation failed then check all the form fields in the cms to see where there is a date and ensure it's in the right format.