Creative camera has free reading and video learning articles that could be useful for u3a photography enthusiasts. They will be added to every two months or so and will be a useful archive, but for now in lockdown they provide something to read and think about.
Go to https://creativecamera.online/photography-tutorials/
There are currently 18 separate tutorials on this page.
Digital Camera World
Digital Camera World have a website page which contains tutorials of tips which they claim will "supercharge your skills, improve your composition disposition, and push your picture taking ."
These tips are in separate sections which cover :