Thank you all for the further comments.
Hokeydokey.............blocking googlesyndication in this version of Opera ( and in the previous version 10.10 which I had reinstalled alongside 10.50 as a tester ) causes the problem..........so avoid in-build Opera content blocker..
As said the ads are not intrusive and do generate a little revenue so old TD can live with them................and on reflection this does remind me of a little issue that I had spotted weeks ago when I blocked the content, but which issue I had forgotten.
In previous versions of Opera, when blocking content, I could select one advert from a whole bunch of them and block that individual item only, leaving the rest in their glory...................however, in this version I can block all or nothing.
Must indeed be a bug in the content blocker which appears to be killing more than it should.
Will post an "error ticket" about that on the Opera webbie
Woohoo...could TD's weeks of frustration really be at an end...