The information I have on Hawkes is from the New Langwill Index. They show:
1860-62, Hawkes & Co, Cumberland St, Pimlico
1862-75, Hawkes & Co, 33 Soho Square
1875, Hawkes & Co, Leicester Square
1876-89, Riviere & Hawkes, Leicester Square
1889-95 Hawkes & Son, Leicester Square
1895-1930, Hawkes & Son, Denman St, Picaddilly Circus
Broad Internet searches reveal that William Henry Hawkes, state trumpeter for Queen Victoria, started an import business in 1860 at Cumberland St. Pimlico. In 1862,he moved to Soho Sqare. In 1869, he added a repair shop. In 1875, he moved to Leicester Square.
The stamp on the metal ferrules (above) indicates that Henry Starck was the maker of these pipes and that Hawkes & Son were at Denman St. in London at the time. The pictures below tell quite a different story. There is nothing to suggest that Starck was the maker, so in all probability Hawkes was sourcing his bagpipes elsewhere. Hawkes published a very comprehensive (86 pages) catalog of instruments in 1923 however I have not been able to find those pages pertaining to woodwind instruments. My conclusion is that neither Hawkes nor Boosey & Hawkes were makers of Great Highland Bagpipes.