Tag attached on lower center of verso, black ink inscription: Thos agenew & sons Ltd / No. 31413 / by appointment to the late king George VI / London, 43, Old Bond Street, Piccadilly, W
Graphite inscription on lower right corner of mat: Is there any evidence for the attribution? It is doubtless correct but there is almost nothing certainly by HB by which to compare.
Red pen inscription on lower center of mat: S