[exim] Sending email via Exim very slow

Hello all,

Have set up and installed Exim, spamassassin and clamav and it all seems to be
working fine tho clamav's logs shows nothing. But anyway, my problem is that I
find when I log in Exim via IMAP using uw-imapd and read all the emails, then
when I want to send emails, it takes a very long time to send - around 10-15
seconds before lines show up in the logs and then it get sent straightaway -
but no error messages in any logs, or thunderbird or anything - do anyone know
what I'm doing wrong to make sending email extremely slow?

Thanks very much for your help in advance

Cheers - Piers