When you have a Plieger thermostat valve you can make the Tado fit by:

1. Filing the plastic nut into a circle
2. Pick one of the extension tubes, for me the 8mm version was the perfect fit
3. Fit the Tado without any adapter

To retry after a E1, E2 or E4 errors just open the battery cover by sliding it, wait for 10 seconds, then close it again and refit

I was inspired by: https://community.tado.com/nl/discussion/3428/tado-thermostaatkraan-icm-plieger-kraan