While logged in to your Google account from a desktop computer, open your calendar, and in the left column, click the down-arrow next to Other calendars.
Select Add by URL from the menu.
Find the Dundee calendar you would like added from the list, and 'copy' it. (If it's easier, right click and there should be an option to 'Copy link address.')
Enter/Paste the web address in the field provided.
Click Add calendar. The calendar will appear in the Other calendars section of the calendar list to the left.