Here is the presentation I was planning to give as a “lightning talk” at the StateOfTheMap conference this weekend. However, there were more speakers than places for these sessions – and quite a few of the speakers failed to appreciate that, by running over the five-minute limit, they would be denying other people the chance of speaking! So I didn’t get to present it. However, you should be able to get the gist of what I was going to say through the contents of the slides.