I had a fiddle last night and somehow all is well!

I am not sure what I did! The last thing I changed were the NTLM authorisation settings but that was some days ago. I noticed this time that authorisation was set to NTLM so I tried a few times changing the "If slow connection,..." and "If fast connection..." settings - ending up with both of them checked, SSL unchecked and then set back to Basic Authorisation and voila!

I am sure I tried all that before but I am not complaining. I think part of it may have been forcing the connection due to changing all the settings a number of times? Who knows.