We are aware that some users may have seen delays to emails over the last week or two. We have been investigating the cause and now have a plan of action to resolve these once and for all.
Earlier today we made a major change to the config on one of our AV /SPAM servers int he cluster here. Assuimg this is successful the same change will be rolled out to all remaining servers tomorrow and Monday and this should see an end to this issue.
We will update this post as soon as we have more details