Okay, in the C:\Program Files\Opera 20.0.1387.91\20.0.1387.91 folder I renamed the opera_autoupdate file to opera_autoupdateDisAb. I take it that should do it? That should be enough to put up a Force Field and keep my Auto Update nemesis at bay?
I don't have to do anything with the following files ... ?
opera_autoupdate.licenses
opera_autoupdate.version
If it is this easy and not exactly Rocket Science, it's mind boggling why the Devs can't just quickly slap in a Check Box in the Settings to provide us the option.
Thanks, Linuxmint7.

Suntana, you're awesome. Opera was always my favourite but had to stop using it to conserve data from the dreaded auto-updates. Simple brilliance. Thank you.