For anyone who wants to do this without a neutral it is possible. Did it 18months ago by getting a spark to put in GLS touch light switches which operate on 433MHz (same as Sonoffs) and they have both versions requiring neutrals and live in live out versions. A lot of research took me there because I had a bizarre setup where most of my switches were live in live outs and one was a neutral version. GLS made sense to preserve the same look throughout the house. Some of my home devices were wired into Sonoff switches. A small amount of basic tinkering with Sonoff bridge meant that the Sonoff app can control Sonoff devices and specified light switches from GLS. Sonoff works, Alexa works. Swell!