WiFi Smart Plug, Mini Outlet Smart Socket, Smart Light switches, Timing Function Control Your Devices from Anywhere, Fit for Amazon Alexa Echo Google and IFTTT Switches and Sockets (4Pcs/Lot)：https://www.amazon.co.uk/dp/B07MMTHS9X?ref=myi_title_dp
These plugs do the job required absolutely perfectly, and at a really cheap price for 4 of them!
I did have a bit of trouble setting them up with my BT router - so I'll explain how I got them working, hopefully others will see this and it will be useful....
First of all, as is mentioned in the instructions and as others have said, you need to connect it to a 2.4ghz network only, it will not work with 5ghz.
Now this part I only discovered by playing around with the app. If you are finding that the plugs just will not connect, you need to choose "AP Mode" in the app. It's at the top of the screen when you go to set up the new plug. It should then load your list of WiFi networks, and you should be able to see your plug listed. Select it and wait for it to connect. Once it has connected you can go back to the app, and within a few seconds it should find the plug and it will be connected.
★REMOTE CONTROL: You can control the power-on/off via Smart Life App even when you are not at home. It's free download App from App store or Google Play, easy to use and install.
★VOICE CONTROL: The Smart WiFi Plug works with Amazon Alexa, Google Assistant and IFTTT, works with 2.4GHz Wi-Fi router without the need for a separate hub or paid subscription service.
★TIMING CONTROL: Schedule automatically. Create on/off schedules or set auto-off timer routine to work automatically. For example: schedule the air conditioner to turn on before you arrive. Auto-off function turns lights and other devices off after several minutes or hours every time you set them on.
★HOME AUTOMATON: Turn on/off your home device at your fingertips to facilitate your life. Universal for most electrical appliances such as fan, water dispenser, water heater, electric pots, TV, humidifier, light, holiday decorations and etc.
★SAFE & ENERGY SAVING: Smart Plug No hub required. Remote control your electrical equipments with Security via Voice Control. Built-in leakage, overload protection switch, supports Surge Protection and effective absorption of the sudden huge energy, protects the connected devices from damage.