With the usual apologies for any cross-posting.
The final piece of the jigsaw puzzle has been slotted into place regarding the provenance of the language and writing system for Iberian manuscript MS408. A new paper, titled 'Reintroducing a vanished Romance language' is available here: https://www.academia.edu/44261539/Reintroducing_a_vanished_Romance_language
The manuscript is largely concerned with the material culture of Medieval medicine, which played a pivotal role in everyday life. With an absence of scientific understanding, the characteristics of plants were interpreted in the context of their use, which is known as the doctrine of sugnatures.
Enjoy and please disseminate to other scholars who may benefit.
Dr. Gerard Cheshire.
University of Bristol.