Firstly, apart from the example on the A12, I have seen a few LEDs being replaced in and around Bromley, but only as a casual replacement, most of which were due to accident damage.
Secondly, from what I gather, the reason for this rather wasteful replacement of 3 year old Lumas (which performed better at night than its successor, the Orangetek AriaLED), is that the Lumas were trailed on this short stretch of the A12 by TFL's previous street lighting contractor, Ringway Jacobs (who were contracted sometime between 2010-2013 and currently cover Newham and Westminster - as far as I can remember), and notably did the street lighting for the London Olympics.
Ringway Jacobs favoured (at the time) Philips Iridiums and also used Indal Airtraces, Thorn Oracles, Urbis Evolos and Urbis Saphires on Mallatite Columns with short brackets. Ringway Jacobs only ever trailed LED (as LED was still premature), however now all of these LED trials are at risk as Ringway Jacobs are no longer in charge:
>
Philips Speedstar >
Orangetek terrraLED > WRTL Luma (now replaced)
> and possibly others.
Since 2013
Bogeys Bouygues (ex David Webster, who also currently runs Greenwich, Lambeth, Enfield, Barnet and Brents lighting) has been in charge, and so far they have done a good job. Normally Bouygues favours Arcs and Fabrikat/CU Phosco on medium brackets, but the LEDs Boygues have used so far are:
> CU Phosco P850
> Orangetek AriaLED
> Urbis Amperas
> Urbis Teceos
> CU Phosco P851
Personally I do like the Orangetek Arialeds as they are slightly reminiscent of the small-shoed Philips MA60 or the Thorn Alpha 4, however my favourite LEDs are the
WRTL Luma,
Urbis Axia and the
CU Phosco P850.
I do also like the
Urbis Teceo 1 and 2 and the Thorn Oxane.