Thanks Eddy.
Clicking "I trust this website" gave the same warning on first attempt (probably due to a timeout) and then was accepted the second time.
I've reported the URL using
https://www.avast.com/report-a-url.phpSearching on
https://support.avast.com for "create a ticket" wasn't very helpful. It says
Search results for "create a ticket"
Total found: 7
But it didn't show any of them...
Just an advert for "Avast Total Care" who I'm sure would charge me £120 like they did when I reported the incompatibility with the Anniversary update.
Puzzled that nobody else seems to have had this problem signing into Gmail today?
Just re-read the Google announcement
https://support.google.com/accounts/answer/7338427 and it is referring to the old login page appearing if javascript is disabled, not java. I don't even see a way to disable javascript in Chrome, so I assume it should be running, which makes it odd that the old login page appears on both of our computers (and in Firefox too).
"The new sign-in page shows up on computers, phones, and tablets. You'll see it when you sign in to a Google app or a Google service on a browser, like Chrome.
You might still see the old sign-in page in these cases:
You use an older version of a browser
You've turned off JavaScript"