A few oddities of OpenStreetMap history files

I've been working with the OSM history data for Great Britain for a while now. This has mainly removing bugs in the initial processing (yup, out-by-one errors mainly) and, as a side effect, working out how to improve the speed of extracting way geometries. En route I have noted a few quirks which may be helpful for others working with the data.

Some of these should be obvious, but I feel that they are worth stating nonetheless.

Where the streets have no name: Coach Road Estate, Washington

Serlby Close, Usworth. The houses on the left are part of Coach Road Estate
Source: © Alex McGregor at Geograph CC-BY-SA-2.0

Microsoft, like a number of other large tech firms, now has teams working to improve OpenStreetMap. A couple of weeks ago they turned their attention to the UK, and asked about some roads apparently missing street names.

I checked a few of these examples using available Open Data sources, primarily those of the Ordnance Survey. For the most part, our existing mapping seems correct: there is no official street name. Many were places like caravan parks and industrial estates, but one really stood out. This was an area on the north side of Washington, County Durham called Coach Road Estate. As I investigated it soon became apparent that the estate is interesting for other reasons too.