I hate it when councils move back to SON they do that up here as well. In Consett's main shopping street we have Thorn Areafloods running 150 watt attached to the walls of buildings in an opposite arrangement. These light the street very well with good colour rendering. There are also modern Urbis post tops installed during the relighting of the town centre. These are metal halide too. However nearly all of the Areafloods have had their spent lamps replaced with SON ones. They also replaced one of the newish Sapphires running metal halide with a ZX2 running SON.
Durham normally do their replacements in/out and don't normally have columns standing side by side. However I have seen it happen elsewhere. There is one in Hexham, Northumberland, where an Arc is replacing an old SOX lantern however it has been like this for 3 years and the Arc is still not connected. It must have been forgotten that's all I can think. Link of location
http://maps.google.co.uk/maps?f=q&sourc ... 75,,0,1.92