Note:
(a) Francis Younghusband
en.wikipedia.org/wiki/Francis_Younghusband
(1863-1942; section 2.1 Invasion of Tibet and Massacre at Guru)
Later the BBC report mentions the "massacre of Chumik Shenko," which actually deals with the same event: British expedition to Tibet
en.wikipedia.org/wiki/British_expedition_to_Tibet
(section 2.1 The massacre of Chumik Shenko: "encountering his first major obstacle at the pass of Guru on Mar 31, 2014
(b) "Wiltshire-based auctioneers Henry Aldridge and Son"