** This post was updated in June 2017 and can be found at this link **
My attempt to define a date timeline for SBDU frame numbers was published in July 2016 and has so far stood up to the test. That blog post hopefully provides some substance and reasoning behind my opinions and shows why I think SB numbers fall into specific years. I wanted to add reasons and facts to back up my theory, I didn’t want to add another random list of numbers to the numerous internet lists that already exist. I found two important periods difficult to define, one of them was the end of the SBDU at Ilkeston. So have things changed since that post was published?