Right folks!!! SOLVED!!!!!
Okay got it on my own. Look at the error in particular the bit where it says already sent at wp-content/plugins/something.php:700
Okay this error seems to be cause by moving files in FTP which for some reason creates whitespace AFTER THE PHP ?> tags at the end of the files as shown in the errors you get.
SO!!
Simply go through each file and remove the space after the closing PHP tag like this:
\E.G
10.
11.//end of program
12.?>
13.
14.
15.
In the example above I had three blank spaces. Just remove them in any affected file and behold all will be sorted.
Cheers
Ryan
Northern Ireland