Yes Mary, updated, even rebooted! I'm fairly comfortable I set a max size of 20MB here. I even upped it to 50MB at one stage in an attempt to allow the large message that was looping in the queue directory through. That didn't work either. I have since had the failing message removed from the ISP queue.
# config show qmail
qmail=service
MaxMessageSize=20000000
status=enabled
# config show clamav
clamav=service
ArchiveBlockEncrypted=no
ArchiveBlockEntrypted=no
ArchiveBlockMax=no
ArchiveMaxCompressionRatio=300
Checks=24
DNSDatabaseInfo=current.cvd.clamav.net
DatabaseMirror=db.local.clamav.net
Debug=no
DetectBrokenExecutables=no
FilesystemScan=weekly
FilesystemScanExclude=/proc,/sys,/usr/share,/var
FilesystemScanFilesystems=/
FilesystemScanReportTo=admin
Foreground=yes
HTTPProxyPassword=
HTTPProxyPort=
HTTPProxyServer=
HTTPProxyUsername=
HeuristicScanPrecedence=no
IdleTimeout=60
LeaveTemporaryFiles=no
LogClean=no
LogFileUnlock=yes
LogTime=no
LogVerbose=yes
MaxAttempts=6
MaxConnectionQueueLength=30
MaxDirectoryRecursion=20
MaxFileSize=20M
MaxFiles=1500
MaxRecursion=8
MaxThreads=20
Quarantine=enabled
QuarantineDirectory=/var/spool/clamav/quarantine
ReadTimeout=300
ScanArchive=yes
ScanHTML=yes
ScanMail=yes
ScanOLE2=yes
ScanPE=yes
ScanRAR=no
SelfCheck=1800
ShowProxySettings=no
ShowUpdateSettings=no
SignaturesUpdated=unknown
UpdateNonOfficeHrs=disabled
UpdateOfficeHrs=disabled
UpdateWeekend=disabled
status=enabled
# config show qpsmtpd
qpsmtpd=service
Bcc=disabled
BccMode=cc
BccUser=maillog
DNSBL=disabled
LogLevel=6
MaxScannerSize=25000000
RBLList=whois.rfc-ignorant.org:dnsbl.njabl.org:zen.spamhaus.org
RHSBL=disabled
RequireResolvableFromHost=no
SBLList=dsn.rfc-ignorant.org
access=public
qplogsumm=disabled
status=enabled
# config show php
php=service
AllowUrlFopen=Off
status=enabled