Ahh, I've just discovered how to easily find threads I've started myself. On the Following page there are what I'd call Sub-headings: Followed Discussions (the default), Followed Forums, My Discussions....
Tap on My Discussions n there you have them!
I also discovered that, on the New page, if you go to the extreme right of the Sub-headings you'll find Looking for Replies. I hope some of us will use that because I've noticed on several occasions that new posts can sit, unnoticed, for a while. If someone comes to the site with a query and they don't get an answer for a few hours they'll probably have gone on elsewhere by that stage; especially if they're relatively new to forums.
Can anyone explain what the New Showcase is for? (on the New page Sub-headings).