As the title suggests. Having looked on Amazon I was going to get a ‘normal’ one and use a smart plug but most are digital power on/off so likely won’t switch back on if using a smart plug.
Would love some recommendations if anyone have any.
Meross has one for the UK that works with SmartThings, but I don’t know what features you get. Change the settings on the page to UK to see the options there.
If you just want one-way integration to turn it on and off, you can accomplish that via Alexa routines with a lot of different brands. I have a couple of Levoit Alexa-enabled models we use this way, But changes made on the device itself or its own app won’t be reflected in the SmartThings app.
Samsung makes its own air purifiers, but I don’t know if they’re sold in the UK. And some community members have reported that the app integration doesn’t seem to work. So I list these for completeness, but hopefully someone who knows more will say if they are working.
We use a Levoit, the wifi version which works with Echo
Create a few virtual switches in ST and tie them in with some Echo commands and its good enough
The Levoit takes care of itself with regard to speed , so i dont need a visual display in ST
I have a couple of Levoit Alexa-enabled models we use this way, But changes made on the device itself or its own app won’t be reflected in the SmartThings app. 
