All WW2 German photos, documents, handbooks and manuals were all released into Public Domain in 1945, due to the Enemy Property Act. Basically, previously copyrighted "WW2" items, lost copyright, as it was considered to be WW2 propoganda, etc.
If the BA is personally giving you access to their files, and they are investing time to research or find the photos you want, make prints, etc. then they can charge anything for those "services".
They released all their photos onto Wikimedia Commons, under the above noted license, as a cooperation / sharing project. This was done many years ago.
Read the license agreement at the bottom of this page:
http://commons.wikimedia.org/wiki/Fi...mberichter.jpg
This agreement allows anyone to copy, share, and distribute any of the photos, royalty free. You would just have to find the one you are looking for in Wikimedia to save yourself the "service" charges.
Mike