Problem with accelog logging between 3-4 hours on Bangle 2

But on the screen itself it showed that it had recorded lots of samples?

Yes - 144K+ seconds worth of samples.

If you toggle it on and off when you're connected to the IDE, do you see any errors?

None

And does require("Storage").getFree() show that there's a decent amount of free space?

>require("Storage").getFree();
=3775872

I am deleting old logs as I go along so that I never risk running out of space.
I will need to run for 4 hrs again to check the value of getFree() at the time I want to stop the recorder.

Can you try a test and see if you can get a 4 hour log ?