how to set date_info->granularity Is there anywhere in the administrators area can I set $vars['view']->date_info->granularity ?

With the recent updates to Drupal 7.32 the date format of the calendar module heading has changed from [month][year] to [day],[month][day number],[year] which looks silly.

I assume granularity has changed from 'month' to 'day', but I can't find where to change it back.

Is this associated with the fixed bug number 355058?
Here is the quick workaround for the issue:
STEP 1: Edit modules/date/date_views/theme/theme.inc and go find line 165.
Change these two lines:
$format_with_year = variable_get('date_views_' . $granularity . 'format_with_year', 'l, F j, Y');
$format_without_year = variable_get('date_views_' . $granularity . 'format_without_year', 'l, F j');

To these two lines:
$format_with_year = variable_get('date_views_' . $granularity . '_format_with_year', 'l, F j, Y');
$format_without_year = variable_get('date_views_' . $granularity . '_format_without_year', 'l, F j');

Note: the only difference is one underscore character added to each line.
Upload the changed file back to your web server.
STEP 2: Go to (YOUR_WEBSITE)/admin/config/regional/date-time/date-views and click Save. If you get permissions errors, try clearing caches.
Before:

After: