The story of the Grenadiers of the 28th wearing French packs comes from the Regimental history 'Narrative of the Campaigns of the Twenty-eighth Regiment' p. 241-242

https://books.google.ca/books?id=oYNIAAAAYAAJ&printsec=frontcover&dq=28th+foot+regiment&hl=en&sa=X&ved=0ahUKEwiI0tvwoLDhAhUywlkKHfaACaUQ6AEIRTAF#v=onepage&q&f=false

Cliff