It's been 6 months since I threw this idea to the forum so I thought I'd just clarify a few thoughts in case it simplifies the requirements.
I'm thinking that a field is added to the database for the topics at topic creation - default as 0 - not shown to the user.
If google has an issue with the topic (by receipt of their alert email) the field for the topic is changed to 1 by myself.
When displaying the thread the field is read and if it is 0 then it executes the code to display google advert. If it is a 1 then the code to display google advert is skipped.
If there could be an easy way to add the 1 for the topic that would be nice - otherwise I'm ok to make the change via SQL.
Hopefully someone will see that this might be "easy" and can give me some guidance.