Hi Lynne, thanks for your help, I have now found the issue. It looks like the account was compromised as /includes/functions_online.php contained no data as well as blog.php
Now I am on my home PC I had a backup so was able to replace these files with my backup ones and everything is back to normal.
I cant believe I didnt see this when looking today, anyway apologies for wasting your time. I am now off to change my FTP password