[exim] Problem with Maildir delivery

I have an Exim config that specifies that LOCAL_DELIVERY is via the
maildir_home transport, yet mail continues to be delivered to
/var/mail.

Before I bore you all with the ins and outs of my configuration
(which, I should add, was working just dandy before I reinstalled my
operating system), are there any resources I should go and look at? I
can't see anything directly relevant in the FAQ or in the mailing list
archives.

Regards

Peter.
--
Peter Whysall
peter.whysall@???