Is Tureplay enabled in the controller App?

Do you have any other SONOS speakers?

True Play is enabled in the app yes. 
I also have an Arc sound bar and sub. 
Thank you. 

Try Factory Reset of ONLY the MOVE. You’ll then need to add the MOVE to your existing system as if MOVE was a new purchase. Take care here because it’s too easy to click on the wrong choice. You don’t want to start up a new system.  All of your music service registrations, play lists, etc. will be maintained if you Factory Reset only the MOVE.

Thank you. I’ll give that a go tomorrow and will let you know how it goes :)

Sadly that routine has not resolved the issue.
With the app open at the Trueplay screen for the Move, when I press the icon on the Move it makes a deep tone as it should and I can also see the screen on the app dim when I press the icon on the Move and it will show as on or off with each press on the Move - but no illumination of the little light to show that it’s actually activated!

I can’t imagine that the LED has broken, but I’m beginning to conclude that’s the case. 
 

Any more thoughts please? How long is the warranty on these? 
 

Thanks

The device warranty will likely be shown on your purchase receipt - I would toggle the LED off/on - maybe make a short mobile video of your action and then immediately submit a system diagnostic and either note/post it’s reference back here and then contact/chat with Sonos Support Staff via this LINK  and see what the Staff can suggest to resolve the issue.

Update:

After discussing the issue with support chat, resetting the Move again, adding Alexa (microphone works fine) the microphone light still doesn’t work and so they have offered to replace the unit by post. They agreed it was a rare issue, but I’m very pleased with their response so far. 
Thank you for your input here also. 

Thanks for popping back and letting us know the outcome - I think that’s the first time I’ve heard of anyone having an issue with the LED on a Move, but nice to hear the matter is being quickly resolved.

Mother nature is never fair. Anything can break and eventually will break, It’s all a matter of probability and time. Even low probability events occur. It adds some cost to the design cycle, but a company can design their warranty costs into the product by including the failure probability of each part into their design calculations.

Of course this is no solace to a user when MY product fails early. If you look at a failure signature, there will be more failures in the first few months than will occur in the next decade or so. There will be early failures and late failures. And, the failures tend to be characteristic for a given model at a given age. Service centers that specialize in model ‘A’ will be very familiar with its failure signature. If you tell them that you have a model ‘A’ they already know what’s wrong -- with very high probability. 

I’m just filling in the returns form and it needs my credit card details. Anyone know why?!
Thanks

I don’t know the details of your transaction, but  it is typical for companies to ask for charging details when they are sending an advance replacement. Exactly how a company uses these details varies, some will charge immediately, and issue a credit on receipt of the return, some will issue a small test charge in order to validate the card details, others will hold the details and charge the card if the return does not arrive within a reasonable period.