my client is unhappy with the video editing of the evening dancing as we havent used the actual audio but used songs that were playing that evening
I would suggest trying to combine the two audio feeds.  If you layer the room audio with the clean audio, it will probably help make things more usable.  Otherwise I would give the customer what they asked for.  Ultimately, I don't think it is your failing to have had blown out room audio when there would be no good reason to use the room audio.

As an aside, you should also consider the legal ramifications of using either the room audio or clean audio.  Unless you have rights to the songs being played, you are most likely violating copyright and if they go posting it online, there is a reasonable enough chance to find yourself sitting on the wrong end of a lawsuit, again depending on jurisdiction and how much attention the video gets.