Herts used to replace SOX like for like up until 2010, nowadays they're using a combination of Philips CFL lanterns (look quite nice actually) and Iridiums. Most of these are, fortunately, on new columns. My approach would be to start a PFI type scheme where these casual replacement standards would become consistent along entire lengths of road, preferably before they change the standards again. Most of the existing stock around here is ancient anyway, 60s and 70s Eleco and GEC lanterns on rusty steel columns.I live in a place called New Ash Green
All the street lights need replacing because some of them are from circa 1975, and the columns are around 1967!
I'd replace the residential road lanterns with SGS 203s, SRL8 running 100w SON-T on small steel columns.
The main road lanterns I'd have MA90s, and on the roundabout I'd have Alpha 8's MK II running 150W SON-T on Stainton tubular steel columns painted Norfolk Green
And then on the paths I'd have Simplex Aries running 55W SOX