They were most likely just sending all emails to see if they could find something they could use…such as emailed bank statements, etc. or they could use personal emails to find out your pet’s name, your wife’s name, kids, etc. to try various passwords on other accounts.
Thanks once again for your help ptireland. I’m still trying to work out when I could possibly have unknowingly entered my email and password on any site apart from my googlemail.
Anyway I’m glad I caught it just as it was starting, so hopefully no harm was done.