Hi,
We are going through the same problem with our "black sheep". We wrote to Strangeways prison in Manchester where he was a 'guest' in 1901 and were told they were too busy to check their records. However, I spoke with the information commissioners office in Wilmslow, and , under the freedom of information act , they must give you the information you request . So, in summary, write to the prison, give as much information as possible,ie full name , D.O.B. what information you want etc , and quote the freedom of information act. They must respond within 20 working days, or give you a very good reason why the information is restricted .
Good Luck
Roy