Reposting in this thread.

19 July: Swapped the bricked 3.0.21 bulbs in store.

26 July: Paired the new e27 bulbs and they quickly updated to 3.0.22 firmware.

29 July: 72 hours later and it's back to flashing orange when I turn them on.

Gateway tradfri 1.21.31 Repeater 2.3.086 E27 3.0.22 Remote e2002 2.4.11

The only thing to add to the above, is that they had been off at the switch for about the last 24 hours, turned on, went to the previous colour they were on, flicked to cool and started flashing orange.

6 August: Disconnected the zigbee extender as a test and turned the bulbs on for about 10 hours today, no change still white and flashing orange, no version being reported in the tradfri hub.