I’ve had a Hive system for a few years and also been interested in the Zigbee query, mostly for fun/experimentation but also to have the possibilty of escaping the clutches of BG’s server. So recently I bought from eBay a boiler controller (Hive SLR2b) to tinker with, not wishing to possibly confuse my real system.
The Hive SLR2b paired immediately with my cheapskate CC2531 easily, no tricks, no fidgeting, no problems. I can send MQTT commands to it and get correct messages back, and nice clunks from the controller as it switches. If Hive Zigbee is a subset, I’ve not yet found what is missing.
Someone clever at zigbee2mqtt has done the hard work; all credit to them.
No excuses now chaps 