Google calendar not syncing to MacOS Calendar (on one device)

Hello, I run several Macs, an iPad an iPhone. At work I use Google Calendar and sync this to my MacOS Calendar. Works fine except one (only one of my work calendars - others are OK) no longer syncs to one Mac. It's fine on all the other devices. The calendar is there in the list of calendars but checking it or unchecking it and checking it again makes no difference. Have signed out of iCloud on the Mac, checked Google calendar sync settings (which are the same for all devices and look fine) but cannot get the calendar to display. It was working fine, and then just stopped.

Anybody got an ideas?