So the final update:
Summary: Fixed under warranty (car bought in 2018 and has 94k km) - now works. Phew!
Discussion: I dropped the car at the dealer on a Friday morning as I was away for the weekend and their first available appointment was Monday. I left them a paper description of the non charging issue as per my post here on 6th July.
The dealer called on Friday afternoon and said: "It's fixed - it was a software issue and the software update has been done". I asked them if they had checked that it was indeed charging, but they said that they didn't have a charging cable. I asked them to use the 110v cable that is in the trunk, and of course when they tried it, the green light came on but it didn't charge, so they said that they'd look into it more on Monday.
The following week, they identified that the battery charger was probably faulty and that it was covered by the Honda basic warranty, but they needed some special tools and gloves to work on the car and these would have to come from Montreal as they didn't have a set at my dealer. (Looks like Clarity repairs are not a normal occurrence). Nothing more was done that week, and the following week, they gave me a rental car as my Clarity had been in the shop for over a week and they had no clear date for returning it to me. They showed me that the repair cost would have been around CAN $5300 but that it was covered under warranty and they also waived the $160 initial diagnostic charge as they had had the car for over two weeks. They also had to return the failed charger unit to Honda Canada before they were authorised to replace it with a new unit.
All in all, the dealership did a good job, even though it took over two weeks, although communication could have been improved, as I had to call them to get status updates. After they had replaced the charger (which took approx 3.4hrs of shop time) they asked me to check that the car was charging using the Honda app, which I did and it was. As the cost of the charger was so high (close to $5000) and I had found some used ones on eBay for around $500, I asked them if they would be prepared to replace the failed unit with one that I provided and just charge me the labour. They said that this would be no problem - they do this for people who bring their own oil and filter, tires etc so that could be a solution if the charger fails outside of the warranty period. I don't think that this repair is anything I'd consider as a home repair as apparently it involves removing the main battery pack with the car on a hoist. Too dangerous and complicated for DIY.
Conclusion: Likely to be selling the car before the hybrid warranty expires at 8 years and 160k km.
Thanks to all of you who made comments and suggestions! I appreciated the "clarity of the insights".
