One thing that any new owner of a Pre-War Austin needs to know is that the Nuts & Bolts are Imperial, well you knew that already didn't you. Well I thought I did, I knew that there were Metric and Imperial measurements and therefore there would be Metric and Imperial sized Bolts. When I first set out I proudly went out and bought a new set of Sockets and Spanners (Wrenches) and set to work, only to discover they didn't seem to fit well, in fact metric sizes seemed to fit better.
Urgh, what was wrong, I had a full set of Imperial sizes so why wouldn't they fit ? Eventually I found the answer, there are more than one set of Imperial standards for Bolts! Around about the 1950's British cars started to use the American standard for their bolts and that remained the common standard for many years until virtually everything went metric in the UK and Europe. As a result any set of sockets or spanners that you buy these days contain metric and AF (American Fine) sizes. What is needed for cars built before that is British Standard Whitworth sized sockets or spanners. Something that will undoubtedly trip up other people who are not aware of this historic fact.