This looks great and a promising start to addressing a long awaited issue within Moodle.
dbs Music is a music production and sound engineering college who developed a Moodle plugin several years ago to do exactly this. We have used it very successfully over the last five years as a tool to provide feedback, track grades and manage verification/moderation processes. Unfortunately, browser updates mean that this plugin is losing its functionality and we are currently migrating our systems into the newer version of Moodle.
This is the first code I have seen which deals with the BTEC grading and tracking issues within Moodle. The main problem I see here is the amount of pass, merit and distinction criteria that have to be attached to an assignment. Some of our assignments have six or seven grade criteria attached which would potentially render up to twenty one grade and feedback boxes. Our current Moodle plugin allows the tutor to award pass, merit or distinction to specific criteria (see screen print). Differentiation between the grade descriptors are achieved by numerical values that directly relate to the BTEC scheme. This provides both the tutor and student a very clean method for viewing feedback and grades.
Could you maybe incorporate a function that allows the tutor to select specific criteria from the grading form when creating the assignment? This would allow full tracking of the unit criteria with enhanced functionality for the end user (student). Also, is it possible to provide grading above M5 and D5 to take into account units with higher numbers of grade criteria?
Really glad to see that there is an emerging Moodle community trying to tackle this problem; it seems that this issue has never really been addressed within the wider community. I am a subject leader for a very large college in the South West of England and I am happy to provide feedback and experience from an end-user point of view. I would love to develop my programming skills to help move these ideas forward but I would need an extra life for this to happen. So, thank you to all you amazing developers and programmers who help solve these problems for the rest of us.