I asked Mike Worthingtom Williams and got this reply. Trying the British library is not a bad idea!
Dear Bob
I have Glass’s check book for cars but not for three-wheelers and motorcycles. These check books were issued only to the trade, and how the DVLA expect members of the public to access them I do not know. They are not all that satisfactory, in fact, with many makes not included and others, like Lea-Francis, simply showing a blank where chassis numbers should be.
The British Library used to be sent a copy of every printed book, and it might be worth contacting them in London to see whether they have the Glass’s check books, and if so if they can let you have a photocopy of the relevant page with a covering letter confirming that it does come from Glass’s check book. I know from experience that quite a few of the DVLA’s local offices are not adhering rigidly to the DVLA Swansea’s dictat, and I am still issuing dating certificates to a number of dealers who seem to be able to use them without problems.
I am on the lookout for Glass’s check books and have recently acquired a number of car ones. If I manage to get the motorcycle editions, I will mention this in my column in Old Bike Mart.
Sorry I can’t be more help at the moment.
Best wishes,
Mike WW
From: Bob Purton [mailto:bobbybubble@ntlworld.com]
Sent: 03 May 2013 14:56