Future suggested amendment to DL submit form

We have summised that a few changes would make the form slightly easier to understand for users in future:

Instead of the the current File, PDF and Plain Text options (and their associated sub-options), change them to the following:

Original (Browse... button) (Offer Download)
PDF (Browse... button) (Generate from Original) (Offer Download)
Plain Text (Browse... button) (Generate from Original) (Offer Download)

The logic should also be subtly different. Insead of the first option (Original) being a mandatory field, the form needs to check that at least one option from the first three (Original, PDF or Plain Text) is selected. If the submitter only has a PDF then they can upload it via the PDF option on the form.