We recently had a question from a researcher in Florence who was looking for statistics on wheat trade in Great Britain from before 1930.
This type of material is found in the library's IIA Collection. I found two publications that would be useful to this researcher:
The London Grain, Seed and Oil Reporter (1915-1943)
Agricultural Statistics of Great Britain (1902-1931)
Because of the age of these materials, they can't be scanned, but they can be consulted in person in our library.