I had a quick flurry of mails this weekend, as if someone had spotted there was a backlog for the past week. Having looked at the headers, it appears the mail infrastructure at iomart.com seems to be the problem. I'm still missing mails, so have raised a support ticket, and provided them with the one of the headers, to see what the problem is. Mails from my work account and my brother have definitely gone missing, and I suspect others may also have gone astray.
Seeing as I work for an email company, I have been considering re-pointing my MX records. It would seem to be a better solution as at least I would be able to check for myself if my mail got stranded. Not that it ever would, of course :)
