Actually I have just checked again and there are a few rated .cr2 files missing not just .tiff
This seems to be a strange issue as when I tried to find the files by browsing by rating then they did not show up.
But when I browsed the folder the files are in they initially did not show up but then after sorting by various things they are now showing up there with the the correct star rating.
Now when I have gone back to browsing the whole catalogue by rating the missing files have turned up.
Is there some background process or similar that is only triggered when you start sorting the files. I added them last night so it has been many hours so is not just a delay in getting into database.
Anyway problem seems to have resolved itself, will have to remember to try some sorts or similar before checking if all the files have got in.
By the way I am scanning in the whole directory again (including recreating thumbnails) as I don't know how to just read the metadata looking for changes in that.