http://www.johnwood.c...-Code-of-Conduct.aspx
See Point 4.
So far as I can tell, although the consumer protection act may require estate agents to declare knowledge of an adverse survey, this doesn't yet seem to have been tested in law.
There is certainly no requirement on them to tell you why a previous sale fell through.
I am not a legal beagle but the problem would seem to me to partly depend on what "adverse survey" means in law.
When we bought our current house, there were various things wrong that needed fixing before we finally agreed to buy. I wouldn't think that would come under the heading of an adverse survey though.
If the previous purchaser decided on the basis of the survey that the house wasn't worth the asking price, I don't think you would get away with calling that an adverse survey either.
You aren't an injured party, not even someone with a "valid" interest from what you have said. So again my question would be why should the estate agent tell you anything?