Nothing is easy, and Google Play continued to throw up "gotchas", refusing a couple of times to be able to process my uploaded .apk file. However, it relented in the end. You can find it by clicking on the Google Play button here.
I've asked for it to be available in the English-speaking countries and the Eurozone. The app itself only "speaks" English, but so do 99% of all apps ever written so I'm not too bothered about that yet.
The next stage is to publish the free "Lite" version with restricted facilities.