Not on much these days just popped on to catch up saw your post and thought I'd add - our LO is just 17 months and has been on 1 nap since 12 months, which is now down to only 1.5 hrs most days....
We were doing 7pm BT until recently when she was having trouble falling asleep and waking early so we've bumped it to 7.30..... She's much lower sleep needs than her brother....occasionally she'll throw a longer nap, but also throws in 1 hr 15s and still is going strong at BT (nickname the Duracell Bunny!)
Can't remember how we got there, but you're not alone.....! It's liberating tbh as it's only 1 nap to stress about not 2!!