passport problem

I am an Irish citizen married to a Chinese woman and we have 2 son's , we have booked ticket's to China ( i have been many times ) . When we applied for the visa's we were contacted by the CVAC and told that there was a problem and we would have to go to London with our son's . When we arrived we were seen and told we would have to go to the passport center for approval as the CVAC told us they could not make the decision . So off we go , son's ,all our relevant documentation and a host of questions . The problem is, that on my youngest son's passport, it does not show his middle name , as this is not required by law . Even though we had his Birth certificate , his passport , his Irish foreign birth's certificate and himself they still refused to give him approval for it. We are due to travel on the 21 of July and do not have enough time to change any documents ,( also as it is not needed by law i don't see why i should ) . What is my best way forward, as i cannot see how much more proof they need than someone in front of them with all the correct documents ?.....p.s. we live in the U.K.