Not sure if it helps, but the https://miles.burke.id.au/blog/feed/ actually spits back a blank page, ie:
‘<html><body></body></html>’
…but the https://miles.burke.id.au/blog/wp-feed.php actually spits out RSS2.0, although not valid, and won’t work with rss readers.
Does this make it easier/harder to solve?
Thanks again folks! ??
Miles.