The guard had Sherlock sign for the gold delivery before all the gold was brought into the house. However, he would not sign until he inventoried all of the cases (at least 9 cases) to make certain all 270 bars were delivered. Additionally, each bar is numbered so they would be checked off of a list.
Holmes mispronounces the poet's name, Yeats as "Yeets" instead of the correct "Yates".
However, "ea" in English is usually pronounced "ee" and some people do choose to use this pronunciation, since it's not possible to ask the poet's opinion, either choice is acceptable.
Each case holds up to 30 bars of gold: 6 bars to a layer, 5 layers deep. Each bar weighs about 6.6 pounds, so each case would weigh about 200 pounds. The guards carry the cases in as if they are very light.
It is clear the music Holmes was practicing conducting was dubbed on later since he is conducting completely the wrong timing for the piece. He is conducting 3/4 (you can even see this as the baton is sketching a triangle), but the piece is 2/4.
It's impossible to make this mistake when hearing the music, a person can't hear one beat and count a clashing one, and someone who can't hear the beat (has no rhythm) wouldn't be able to count any beat.
After quoting W. B. Yeats, Holmes pronounces his name to to rhyme with "beets". Any American who has studied Yeats more than superficially, and ANY Brit, knows that his name rhymes with "Bates".
Baskerville mentions "obituaries" written by Norman Horowitz when Sherlock and Joan come to see him. Up to this point in the conversation, Holmes had referred to a "list" and "predictions," but at no point specifically does he say that Horowitz had written "obituaries" about people who were going to die.