Go to preferences, Advanced tab, click on Security switch Auto-update option to your choice.

Thank you so much for that, I must have trawled these options so many times yet missed that one! Much appreciated

How to stop Opera asking me if I want to update? I am using the last of the old (best) version, and I DO NOT want to upgrade to the Chrome mess. I will stop using Opera if I have to do that. But sick of every time I open my PC at home and in the office, I have to cancel the tab before I get access.