"There is any difference if you disable hardware acceleration?"
@leocg, I don't think so. That is something I did do at some stage in the battle but did not see any effect one way or another.
I have now downgraded to V40.0.2308.54 and will monitor how that goes. One enraging part of this was realising Opera was auto-updating and "upgrading" to v43, thereby thwarting my attempts to do further diagnostics. X/
I note a past post you have made about companies not wanting users on old versions and I can understand that but it was like pulling teeth killing the auto-update. It really shouldn't be anything other than a toggle On/Off option, set as On by default.
Thus far, other than the built-in adblocker screwing the format of this page, things seem to be OK. I will not be using the Opera VPN but will, after some running under normal conditions, use my own commercial VPN - assuming I don't hit the same issues with this version.
EDIT. Just as I tried to post this I got the page not loading problem again. I'll turn off hardware acceleration now and if the problem is not resolved by that I'm done. I'd don't have the time to spend or the will to expend on a browser that won't work on a basic level. I'll uninstall and go back to Firefox.