Hi Harriet, I'm in a very similar boat, DS is 20 mo and no cycle yet. I'm going to start cutting down on feeds on a couple of weeks too. DS feeds morning, bedtime and when I get back from work. On days I'm not working he may have another feed during the day.
Think I'm going to start by dropping the getting home from work feed, its normally just before dinner so only a short time to have to distract him!
Have you thought about dropping the feed when he wakes up after bedtime? I've read that stopping feeding at night can help to get things back to normal.
Also there is a thread in conception for ttc while bf, I was on it, but now I've decided to reduce or stop bf I've left it. Lots of advice and support there though, and some bfps to show it can be done.
I had what felt like ewcm for several months before I got my cycle back, so I wouldn't rely on that.
It really does seem to be the night stretch that matters. For us, one week of banning feeds between the 7pm and 7am feeds did it. And that was with co-sleeping (offered water instead). He was pretty cross but hey.
We went back to practically fucking hourly night feeds later on without any effect on said cycle though, so it can work as a temporary measure.