"NHS Records service"

My wife was admitted in 2010 to the Cheltenham general hospital, with what appeared to be stroke like symptoms. She is an American National and stayed in the hospital for 8 days 2 in A and E and the rest on the stroke wards and she had multiple tests done from CAT scans to lumbar punctures. Because she was residing in Germany at the time of the sickness and has german health insurance, the hospital said they would charge it to the German insurance. We are now looking to apply for a spousal visa and need to have written proof that there are no more charges relating to her discharge. We went to Cheltenham General but they said even though they can tell us they cant see any outstanding payments, we need to get a permission to release her records as part of the Data Protection Act. We have no idea where to begin and are stuck and need help, we have gone through all the channels we can exhaust and this is our last hope.

Please help.