Some UK members are doing something similar by putting a box or a blank over an existing UK switch and then mounting the battery operated POPP switch on top of that.
These are working with a community-created device handler.
Device handler for the UK switches:
One of the project threads on building the Popp into a blanking cover:
The Z wave.me, popp, and devolo switches all use the same device handler. They typically cost around £40. Each of the four corners can be depressed independently so you get multiple functionality. These are only available on the UK zwave frequency.
Follow-on questions on these devices should be asked in One of the threads above. But I just wanted to mention their availability as a UK option for a similar use case to the linear smart switch cover.