Sometimes the spreadsheets are the output of one system, but the input to the next: the spreadsheets of the Office of National Statistics in the UK are the final, and official output of a long chain of number wrangling, but when it comes to re-consuming them to power their new data-driven website it's a real challenge -- I wound up working on a project to allow programmatic consumption of these complex spreadsheets.

(https://github.com/sensiblecodeio/databaker for the top-level project; https://github.com/sensiblecodeio/xypath for the library I created).

Get in touch if you're interested -- dave.mckee@gmail.com