I am on holiday in the Cotswolds and the local WiFi goes via an IPv6-savvy ISP (unlike the one at home). As a result I can read web sites via IPv6.
First I checked this by visiting Test Your IPv6, which has a list of sites. Then I tried https://ip6.alleged.org.uk/, the copy of my site that is on an IPv6-only address. It works! And when I visit one of the sites I have ported over to my new server, the site works as it should and checking the logs shows my requests are arriving from my IPv6 address.
Finally a chance to make use of the work I did in 2012 to add IPv6 support.