Many thanks for your reply, Brian.
With your help, I seem to have resolved the situation, referring to the attached screenshot.
A. This shows the apparent barometer flatlining.
B. In Control panel/offsets and initial rain/temp/baro offsets/rain totals, I reset Barometer Offset to 0 mbar. From there, it oscillated at irregular intervals between the pressure at sea level and corrected for altitude.
C. Attempts to see what happens by changing the Barometer Offset, making things worse!
D. on the Main Unit, reduced the altitude setting to 0 m. It now plotted the real altitude pressure correctly.
E. I reset the Barometer Offset in the control panel to 32.5 mbar, corresponding to the sea level altitude correction here.
Everything now seems to be working, comme il faut!
I must admit that I really hate making adjustments to the Main Unit which I firmly believe is the worst abortion of firmware yet devised by man! It is a pity that OS has neither improved it nor replaced it by something a lot better.
Thanks again, Brian!
