How can one get a replacement of decree nisi without spending 40 quid?

My partner is due to claim his State Pension but has lost his divorce papers, they are bound to ask the date and the silly old fool can not remember. He went to the appropriate place and they said a search would cost him 40 pound, he has been on incapacity since a bad accident in 2000 and has not got that amount to spare. Is there anybody know if we can search ourself and how? Thanking you all in anticipation of your help.