Gents. Thanks for the posts, really appreciated. In all cases, the couches are pre-inspected as part of the procedure.
I think in this case the techy looked at this and decided that, because he's cleaned hundreds of them without problems, then this did not need any special treatment.
Our process for cleaning any couch is not to use any solvents what so ever. The reason for this is because I'm not cleaning them, someone else is. In order to avoid problems we provide the techy with the simplest and most gentle process and chemicals possible so that he is unlikely to make a mistake.
Having said this the techy did point out the problem and was told to carry on
I think we need to look at our processes to see if we can improve and prevent this from happening again.
Jeremy