At the same time as I moved my mail handling to a different server, I also made a tiny tweak to my procmail settings.
Can’t remember now why I did it, or what I thought it was going to achieve. What it did achieve was to get procmail to throw away random pieces of email.
Anyway, it all seems to be fixed now, but if you sent me something in the last couple of weeks and didn’t get a reply, then that may well be the reason. Please send it again.