UK Power outlets

If you want a cheap no-nonsense ST/Alexa controlled power socket, i’d go for this. You can get 2 for under £34 (50% off second one).

https://www.ebay.co.uk/itm/Heiman-HS2SK-Z-Smart-Plug-White-/253260185417

I’ve a number of these and have had no issues. It is also a Z-Wave repeater.

If you want a Zigbee repeater, the Smartthings power socket, which has been hard to find recently, is now available here:

Both give power usage readings and out of the box local processing (ie. no need for custom DTH)

Note that there have been some concerns with the ST socket overheating: