Rosie Ram and Mark Hallett are working towards a show of Henderson colages at the Tate in December 1919. I went back through my archive and found an envelope containing X Rays borrowed from the Norfolk and Norwich Hospital. The envelope, together with its vain plea for return to the Hospital, was countersigned by A.J.Stevens, then Assistant Principal at the Norwich School of Art, and dated 16th November 1965. It is possible that Nigel would have acquired the material for his own work, I suspect it was originally acquired for a project he was running at the Art School. It could be you studied with Nigel at this period and might remember. If so, contact me.