Ciphers Used in Letters of Oliver Cromwell, Henry Cromwell, and Others

I updated an old article "Codes and Ciphers of Thurloe's Agents" for the first time since 2012. The original article was based on Thurloe State Papers in print, but I noticed the original manuscript is in Add MS in the British Library, based on which I added a new section "BL Add MS 4166". Although the title of the article refers to "Thurloe's Agents", ciphers used in letters of Cromwell (Add MS 4166, f.87-91) and his generals and ambassadors are also covered.
One scheme interesting for me is a kind of polyalphabetic cipher for Henry Cromwell (1656), in which a plaintext letter is represened by a pair of figures, of which the difference indicates the letter (Add MS, f.77-78, 118-119).