rule 320b

Hi just needed some advice. My husband has been refused a visa under 320 (b) because he went back to india before the 17th march. He arrived in India 5th march and submitted his application in the BHC on the 6th march.
My husband was advised to return back to india before the 1st of april and to apply through the proper channels and his stay in india will be temporary. We followed all the instruction and he was asked to come in for an interview on the 22nd april. The ECO was happy with the interview and paper work but refused him because he does not come in with the concession period. My argument is, if I had known about the concession period I would not have sent my husband beforehand. I sent him back to india based on what we were instructed and it's not as he was deported.. he went himself. I have submitted an appeal but I don't know how long it will take to hear back from them, would you know?
Also I feel that their decission is very unfair..please advise of what I can do from here.

Also ask them to reconsider because they have updated the concessions for spouses on 15 May 2008.