Last minute bug

I found a bug this morning which I'll need to fix before release.  I normally run my T6 recording altitude rather than barometric data.

In the office at work yesterday it was pretty warm so I switched the watch to pressure to get a temperature reading.  I forgot to change it this morning when I went out for a run, tried to synchronize the data and ran into a problem with the import process (because there are no altitude readings).

Probably I'll opt just to catch this error but I may not have time to decode the alternative representation (assuming there is one).

On the plus side, the website (such as it is) is ready.