Im waiting for the new sonoff stuff to become more easily available in the uk
its all zigbee 3.0 but nothing on the zigbee site saying so, not the smallest or great looking devices, I just want the windows contacts changed as you say so time spent keeping them connected in reduced
Any Zigbee Door/Window Contact sensor should work in the UK.
Ecolink is a decent brand and while these are new, the few reviews seem positive. Ecolink 4655BC0-R And at 10 for $50 plus shipping, it's hard to beat.