I think that's a typo, Etch, I've checked the A-Z, Wikipedia, Google and the London Encyclopedia and an AA map and they all say there's only one East Smithfield
There’s Aldgate station and there’s Aldgate East station a bit further down the road. The Royal Mint used to be near there. I don’t know if that helps.
everybody's right, it was in Royal Mint Court, which is still there just off East Smithfield, though it's half a mile south of Aldgate station. But it's only 10 letters.