I am pleased to see your trip to Lincolnshire was useful Graham, a few of those pieces look familiar and good to see you got them back to Canada safely in your suitcase, it is amazing what comes out of two Saturday mornings browsing old paper, I guess we are all guilty of not knowing what we have in our files, I had never noticed that listing of the K3's before you found it, those books were bought here in England back in the 1980's and in my literature files for years, long before I knew what a K3 was.
Keep digging we never stop learning until the day we die.
Malcolm.