Hello, Alexender,
In Koch's book which I cited in full it sadly just says 'British Library', without mentioning the manuscript. So: sorry.
Honestly, I do not believe that the items you encircled are actual lengths of matchcord. If you look at the sources I posted at the beginning, on top of this thread, you will notice that 15th and early 16th c. matchcords were much thicker than these seem to be.
Best,
Michael