15-year old daughter going on School Trip to China Refused Visa because my name has changed.

My name on my passport is my Maiden name. My name on my daughter's birth certificate is my Married Name, although my Maiden name is also on the birth certificate. In the UK we are legally entitled to revert to our Maiden name on divorce without changing our name through deed poll. However, the Office has said they will not grant my daughter without a change of name by deed poll. Please can you explain why this is the case?
We have submitted the following documents:
Original Birth certificate, Father's passport, Mother's passport, change of name document, application signed by both parents. What more can we do? My daughter has been studying Mandarin for 4 years in order to go on this trip.
The trip is for 2 weeks and they are leaving on the 12th July 2015.