[Exim] Timing out of frozen messages

Hello,

I would like to time out frozen messages after 7 days, and have put
'timeout_frozen_after = 7d' into the Exim config file, however I never see
any frozen messages older than 48 hours when doing an exim -bp. Can anyone
suggest what I might be doing wrong?

Thanks.
--
"Women and cats will do as they please,
and men and dogs should relax and get used
to the idea." --Robert A Heinlein