Profile missing - not synching

Hi, I am using Lightroom Classic 7.3 with camera raw 10.3 on a Windows 10 PC, 64 bit.

In previous versions I have created import presets and one thing they would do is to select a particular camera calibration profile.

I have two camera types - a Fuji X-E2 and a Canon 5D III. On the Fuji I would generally set the profile to Camera PROVIA/Standard. On the Canon I would use Camera Standard.

I have imported a shoot that is on the 5D III but used the import preset for the Fuji in error. The result is that in the new layout for the Basic settings I see the "Profile" says "Camera Provia/Standard" and below that an exclamation mark and "Profile missing."

I assumed this wouldn't be a problem. I opened the dropdown and chose "Adobe Standard". (I've also tried opening the Profile Browser and chosen "Camera Matching>Standard" to match what I would have done before before anyone suggests that I try that.)

So I now have one image of 160 odd from the session that is set at at "Adobe Standard" (or "Camera Matching Standard" as per my second thought above).

Clearly I don't want to do that to 160 odd images so I select them all and hit "Sync..." - which is what I've had to do in previous versions when I've screwed up on import.

I've tried Synchronise set to "check all". I've tried it with just "Treatment & Profile" and "Process Version" ticked. I've tried it with "Process Version" and "Calibration" (i.e. what it used to be) and I've tried it with "Treatment & Profile", "Process Version" and "Calibration" all ticked.

In every case I can not get the profile to synchronise. If I synch other settings they will synchronise but the profile refuses.

I've also tried "Previous" to get the profile copied over from the previous image and that failed too.

I went to some other images I've imported (correctly) today and they work fine. I can change profile and they sync just fine. But this one session, with the incorrect profile, is failing.

Any bright ideas before I go and edit them one by one?