Take a laptop or tablet with you, you can download the pdfs of the ORBs month by month for free at Kew, you have to pay if not on their internet access. If there are photos etc in an ORB which you can view in the pdf but which have not been copied at particularly high quality you can fill out a request to view the file in paper form. I have had to do that once or twice with WO 208 escapee reports when they started digitising them but didn’t do every report from each file.

Station ORBs and misc units are in hard copy only.