Looks like my WordPress RSS2 setup wasn’t conforming to the tighter set of W3 rules that Apple are using for Safari and Mail subscriptions. I’ve rejigged the setup so that it sucks much, much less.
The feed is now
Please use this feed if you’re using an older one with “wordpress” in the URL. This’ll be the feed URL going forward.
Thanks to everyone who dropped me a note or comment about this. Sorry for the inconvenience…