For clarity: I give Apple support 10 out of 10 - brilliant listeners and able to interpret an issue and provide a decent solution.
I connect my Canon camera, or put the flash card in the slot in my Mac, or connect my Windows phone. They will not show as a connected device in Finder but I can then let Apple Photos do its stuff as it automatically recognises the devices even though they are not appearing as connected. Once imported into Photos I can keep the images there and export the originals to the folders I choose.
Or I can use the Apple Image Capture App (which recognises them as devices) to import the photos directly into the folders I choose without having to go through Apple Photos.
Whilst I have not previously experienced security problems with various software programs auto downloading images when connecting a device I do appreciate the potential for risk. I also appreciate that this "new" way means I have to think about what I am doing and physically take an action to "authorise" the download from the device through an Apple app which if it adds up to a more secure MAC, that is fine by me.
Thanks to all those who put forward suggestions - it was good as it helped me be clear in my own head where the issue was.
For further clarity - I am not an Apple employee and have only a basic IT literacy. Just glad that they are available on the end of a phone and really do grasp the human element of it all - me.