Is WU working OK on my PC or not?

I generally run my Win 10 PC 24/7. I usually close certain tray icons early in a session. So their re-appearance when I start work each morning tells me my PC has restarted overnight. IOW, there has almost certainly been a WU.
Q1: (One that I've been meaning to ask for months.) Why is there is no explicit notification, pop-up message, or whatever from MS that this has occurred, telling me what version was updated to what?

Typing winver in the Run box tells me I have Version 1703 (OS Build 15063.540).
Q2: Is that the latest?

In Event Viewer I see many entries for Event 200, including some earlier this morning (at the time when I manually rebooted after updating a program). Its Properties summary is "A connection to the Windows Update service could not be established."
Q3: Why would that arise?
Q4: Doesn't it contradict the fact that an automatic WU apparently occured last night?
Q5: What no-brainer quick test will tell me whether my WU is working OK or not please?

Terry, East Grinstead, UK

Q2: Is that the latest?

One can check the Sticky threads in the Windows 10 News subsection of TenForums. There are usually three: Insiders, 1703 and 1607.

Q5: What no-brainer quick test will tell me whether my WU is working OK or not please?

A two-step process: check in Services to see if Windows Update is not disabled, and go to Settings and run Windows Update.

Q4: Doesn't it contradict the fact that an automatic WU apparently occured last night?

You've offered no evidence and made an assumption an OS Update occurred. Windows Live Tiles may have been updated, and they are not part of the core OS. Also, apps from the App Store may have been updated.

Insufficient data to answer Q3.

Preferences in Settings may affect how the information is conveyed for Q1.

1. Unless you have turned it off there is an Action Center icon in the Notification Area [formerly called System Tray] next to the clock that will only be an outline in white and the whole box will be white if there are notifications of something that happened, click it to read. Such notifications will or may not, as mentioned, be shown for third-party programs or maybe some minor items.

Thanks both, appreciate the help.