Finally, some positive news
I continued with my attempts at updating the firmware on my outside Hue Motion Sensor, having had a break overnight. I couldn't get it to work and it seemed stalled at about 60% with continual "wildcard" error failures.
So I removed the device from the outside porch and moved it within a couple of metres of the HE but that didn't help as the errors still continued.
I then, got a new outside Hue Motion Sensor I had in stock, discovered it into the Zigbee network and invoked the firmware update, and the result:
sys:12021-05-05 15:04:56.880 Firmware for Side Door Motion Sensor, Philips 100B-010D-42006BB7 is up to date.
sys:12021-05-05 14:46:37.234 Firmware update for [name:Side Door Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 100% complete.
sys:12021-05-05 14:33:37.271 Firmware update for [name:Side Door Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 80% complete.
sys:12021-05-05 14:20:40.761 Firmware update for [name:Side Door Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 60% complete.
sys:12021-05-05 14:07:44.370 Firmware update for [name:Side Door Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 40% complete.
sys:12021-05-05 13:54:48.680 Firmware update for [name:Side Door Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 20% complete.
sys:12021-05-05 13:41:41.804 Starting firmware update for Side Door Motion Sensor, Philips from 420062AD to 42006BB7.
Emboldened by this success, I removed the batteries from the Porch detector, counted to 10, re-installed the batteries and invoked the firmware update, and the result:
sys:12021-05-05 15:38:52.688 Firmware update for [name:Porch Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 100% complete.
sys:12021-05-05 15:26:04.836 Firmware update for [name:Porch Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 80% complete.
sys:12021-05-05 15:13:08.977 Firmware update for [name:Porch Motion Sensor, manufacturer:Philips, imageFileName:100B-010D-42006BB7, fileVersion:42006BB7] is 60% complete.
sys:12021-05-05 15:09:03.104 Starting firmware update for Porch Motion Sensor, Philips from 420062AD to 42006BB7.
So I think the trick is to have the device close to the HE and take the batteries out if it gets stuck with a "wildcard" error.