I have just tried adding these lines to my /etc/hosts file:

127.0.0.1       partner.googleadservices.com
127.0.0.1       pagead.googlesyndication.com
127.0.0.1       pagead2.googlesyndication.com
127.0.0.1       domains.googlesyndication.com
127.0.0.1       adservices.google.com

This fixes the problems with concertina.net, but doesn't fix the issue with newsdaily.com - that one still hangs waiting for partner.googleadservices.com, but hitting the back button reloads it immediately. Mudcat looks the same as before the change, but then I already had ad and script blockers on the case for that.

This way of dealing with the problem is something of a nuclear option - data from those sites never even reaches the browser. I'd rather not have to do any blocking, if only advertisers weren't such utter selfish pigs about using up my communication and processor resources.