Have you tried this? Might find some primary sources on there... if you're lucky...

Sadly, I have to tell you that the book you want, 'The Making of English Law vol 2' by Patrick Wormald, was never written because he died of alcoholism or related illnesses.

Otherwise I suggest asking little_details or medieval_studies.

AHAHAH. This is what you're after. The previous one is available on googlebooks too, but apparently not the next volume.