Barry Taylor (British Library) has reported a new Dee item in Dr William’s Library, London.
It is no. 490 in the Bibliographical Society’s publication of the facsimile of Dee’s catalogue (Roberts and Watson, 1990): ‘Vite de piu eccelle[n]ti artichitetti, pittori &c da Giorgio Vasari: 4°. 2 tomis flor. 1550.’
http://www.bibsoc.org.uk/content/john-dees-library-catalogue