Thanks for your reply.
Maybe I didn't make it clear in my first post but I'm not looking for emails.
I know the emails are on my Yahoo server, I can read them and delete them.
But I have a folder called "recent" which is not an email folder it's an address folder in my email "contacts" and it contains a list of all the email addresses I have ever received an email from since having the phone.
There is no such "recent" folder on my server, hence the reason for me supposing it might be on my phone.
I'll see if I can post a screen shot.