Prodrive,
Click user CP.
Click edit options(on left) a window will pop up
then under messaging & notification banner alter the default thread subscription mode to No email notification.
into user cp
edit options look for
Default Thread Subscription ModeWhen you post a new thread, or reply to a topic, you can choose to automatically add that thread to your list of subscribed threads, with the option to receive email notification of new replies to that thread. Do not subscribe No email notification Instant email notification Daily email notification Weekly email notification Default Thread Subscription Mode:
go in to your profile look under browsing options ,down to automatic thread subscriptiom mode and move the dot to the box marked do not subscribe instead of instant email notification
should sort it for you