Looking for new TRVs to replace old (and slow) Danfoss I got some Remotec that are rebranded ZVIDAR Z-TRV-V01. On their site (Thermostatic Radiator Valve) ZVIDAR list them as 700 series, but the latest are 800 based. To get them working well also with Alexa none of the standard Hubitat drivers would do. Hence this driver you can find here https://github.com/reneboer/Hubitat/tree/main/ZVIDAR.
Oddly the speeds is only 40Kbps where I would expect 100Kbps for an 800 device, but that may be a battery saving option. Also when using S2 secure communications I see a lot of re-routes when a lot of commands are sent. This only happens when doing the device configuration and the supervised mode in the driver does do retries in this situation. Otherwise the device works as expected. In insecure mode the communication seems faster.
Note: after a couple of days I am not using secure S2 on these anymore. It does not work well and sometimes even blocks all Z-Wave traffic. In unsecure mode they seem to work fine.
My office room is nice and warm now. Let me know your experience.