Hi, Rusty!
I have just Googled and come up with this....
Sir Moses Haim Montefiore,1st Baronet, FRS (1784-1885 ) was a British financier and banker, activist, philanthropist and Sheriff of London.
And yes, you have remembered correctly from somewhere that Montefiore is a Jewish banking family!
I wonder if Hugh Sebag Montefiore is a descendent of this family?
Good hunting with sorting out the choice of books about the Somme.
I appreciated Lyn Macdonald's book on such. I liked the slant she gave to her (history) books with the enclosures of letters between soldiers and their loved ones, plus diary entries.
(Sorry it's so cold!)