It would seem that I'm not getting all my notifications from IJ. I just found out via noticing replies had been made and having to finally check my spam filter before I found the notification.
I have no idea why this is happening with some replies and not with others, although it does address a couple of issues I've had recently. But if Dustfinger seems to be late replying to you it'll be because I haven't checked my spam files - although I'll be doing that several times a day from now on.