As an update, I’ve just firmware upgraded said bulbs (GU10 / PAR16s UK older Lightify branded bulbs) to the latest 0x01020510 via the Lightify gateway and they are now not recognised by Hue at all! They flash as if they are joining but do not work. From reading on other forums it appears that Osram are not in the least bit helpful about maintaining compatibility…
It may be possible to join these bulbs via Touchlink to Hue, but getting a GU10 in a downlight enclosure close enough to the Hue hub 12 times over is not a project I’m going to bother with.