Hooray!! I have at last successfully transferred and saved the data to FIS-Control. I deleted all the .DAT files and partial downloads, and when I established the Bluetooth connection discovered I had a third COM Port. So I used that port and as soon as I went into Transfer - Send, it appeared it was using the CRC protocol (I didn't change anything).
The data was quickly transferred. However, I found that the labels only appear if you are in Single Measurement view, and they appear under the value, not at the top of the screen. So I changed the View setting for all my presets to Single Measurement.
Now I can play around with the different views to get the optimum setup.
Thanks for sticking with me Stefan - this has been quite an adventure and has required a lot of patience from both of us.
I'm going to start a couple more threads shortly, but hopefully they will take less time to resolve!
Final word: I went back to File Explorer on my laptop to see which .DAT files were left - the ones I had deleted had all returned, but with different extensions!! Work that one out