I post the headers in the hope that somebody can offer enlightenment...
(NB: I have SAUCE set to the most lax settings possible.)
From firstname.lastname@example.org Wed May 19 13:17:09 2004 Return-path: <email@example.com> Envelope-to: firstname.lastname@example.org Received: from pnnwmp06.egg.com ([220.127.116.11] helo=PNNWMP06.egg.com.) by chiark.greenend.org.uk (Debian Exim 3.35 #1) with esmtp for email@example.com id 1BQQ0S-0001Bk-00; Wed, 19 May 2004 13:17:08 +0100 X-SAUCE-Warning: (chiark.greenend.org.uk) Syntax error in HELO domain +`PNNWMP06.egg.com.' Received: from pnnwmp06.egg.com ([18.104.22.168]) by chiark.greenend.org.uk (SAUCE v0.8.1) with esmtp id sauce-8358-1084969-1; 19 May 2004 12:17:08 +0000 (GMT) Received: from mail2.pn.egg.com (unverified) by PNNWMP06.egg.com. (Content Technologies SMTPRS 4.3.12) with ESMTP id <firstname.lastname@example.org.> for <email@example.com>; Wed, 19 May 2004 13:21:04 +0100 Message-ID: <firstname.lastname@example.org.> Received: from pnnrsp05 (pnnrsp05.pn.egg.com [22.214.171.124]) by mail2.pn.egg.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id KZY1ZVC6; Wed, 19 May 2004 13:15:36 +0100 X-Mailer: EMailSend TE Service Importance: HIGH Sensitivity: PERS Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="6c4887cd-c1ce-4572-a288-438c69177cb8" Content-Length: 11461 Lines: 190
Update: Problem solved. I'm dozy, and the text of the mail is in attachments, though I'm not sure why they weren't flagged in the body of the message as they usually are. Thanks simont and ewx.