There is a particularly difficult knot in one part of my family tree. Like many places in the UK, when Middlesbrough first boomed there was a massive influx of people to the newly created jobs and almost no housing had yet been built. The net result is that the census shows 22 people living in a certain house, five of whom had the same name. All were more or less the same age and all had the same job. Deciding which one was my ancestor is tricky.