Purchased one of the 900 series from Screwfix today and it does work via IFTTT (set up the device following BG instructions / Open IFTTT account / Link ST account and BG account to IFTTT through the app / create automations through IFTTT
Downside is that IFTTT allow you 3 automations for free and after that you need a Pro account for £4.99 p.m and you need 2 automations for each plug socket - on and off
An alternative control can be achieved through the Google Home app linking to the BG controls