In my previous post I suggested that the initials transcribed by a British Library cataloguer as "J. M. W.", that are inscribed on the back of the miniature shown above, should in fact be read as "T. M. W.", the initials of Thomas Miller Whitehead.
I have now found near-certain confirmation that he did indeed own it.
In W. R. Tymms and M. D. Wyatt's The Art of Illuminating as Practised in Europe From the Earliest Times (London, 1860), is this footnote:
" [...] a grand leaf from a folio, on which is painted a seated allegorical figure of "Rome", in the possession of Mr. T. Whitehead [...]"and on a following page, in a discussion of Apollonius de Bonfratelli, he is referred to using the initials of both of his forenames:
" [...] Some beautiful specimens of his handicraft remain in the possession of Mr. T. M. Whitehead. [...]"It seems likely that these are the same Bonfratelli items exhibited, together with the above "VRBS ROMA" miniature, two years later at the South Kensington Museum -- by then the property of Robert Holford.
It may in fact have been the publication of Tymms & Wyatt's book in 1860 that alerted Holford to the treasures in Whitehead's collection.