It is worth noting that Google only updates its imported Calendar files around twice a day.
So bearing in mind the update for new appointments will happen roughly every 8 hours. Which is probably fine for appointments after the day you enter them. But for today's appointments that's not great! This is down to Google because Google Calendars Caches their own calendar file which is why you can't simply manually refresh by refreshing the page, except by adding some spurious text on the end of the URL each time - a pain!
To add a Webdadi Diary to Google Calendar do the following:-
Login to your Google Calendar
Click Other Calendars – right hand side dropdown list.
Click Add by URL
Enter the following URL: http://<hostname>/icalendar.ics?username=<username>&password=<password>
Remember to remove the <
This also works for Outlook by the way as well but Microsoft updates its subscribed calendars relatively regularly.
If you want to do a manual refresh of the Google Calendar you will need to append the URL above with ?version2 or whatever version number you choose. By changing the physical URL, this changes the filename thereby giving you a refreshed Calendar.