I’ve been trying to set up a new special offer topic today (finally got it working) and it was fiddlier than I thought. 
On the upside, it turns out you can delete your topics at TL2. 
Though I have just tried to delete one of my really old topics and that didn’t work. Maybe it’s because it had replies? Or was an imported one from the old place? 
I am also out of edits for the day (again), so maybe it’s that. (I could edit to put this in as it was within the 5 minute ninja edit window )