iCal - Am I being a complete IDIOT :)

HELP!!! I think I've fried my brain.... haha thinking to much about London Marathon on Sunday :)

I am trying to add external calendars that are published as an iCal from a different server (SuiteCRM) Groupwise documentation for 14R2 it says:-

Manually Subscribing to an Internet Calendar#

  • In the Folder List, right-click the main GroupWise calendar, then click Subscribe.

  • In the Location field, type the URL of the Internet calendar you are subscribing to.

  • In the Folder Name field, type the folder name for the new Internet calendar.

  • In the Update Frequency drop-down list, select how often you want the calendar contents to be updated.

  • Click Subscribe.

OK.... So I am being utterly dense but there is not SUBSCRIBE option???

So I have a url