Yes ...

And I've found that the XML link that I'd entered to setup the calendar in the first place is different from what is listed online in my Google calendar. I don't understand why it's changed.

I just had another look at it ... first off, I entered a couple of events to my Google calendar through my phone. These have now shown up in the Lightning calendar. What's more, I can now enter an event through Lightning and it syncs without any problem to Google!!

Go figure. What's going on? Is this a Google issue perhaps?

Ever since I upgraded my Thunderbird to 31.2.0, and Lightning to 3.3.1, the 'save and close' button quick working. I click it for either creating a new event, or editing an existing event, and nothing happens. I have to either click the 'x' to close, and then choose 'save' from the warning prompt - or choose event/save menu option and click the 'x'.

Quite a nuisance! Any fixes?!

Is this what is happening to you Parky?

What fixed my issue was a complete uninstall and reinstall of TB 31 and Lightning 3.3.1. Now the save and close is working again.