Finally paired it after countless hub reboots and attempts at resetting the bulb. Here’s what I did.
Rebooted my hub.
Bulb on off 6 times. Then for the first time saw the bulb very slightly flicker. Blink and you’ve missed it
Left it off for about 30 mins
Add a thing
Bulb on
and hey presto it appeared as a thing. Renamed and saved it then changed it to ZLL dimmer bulb in the IDE.
Done