I can't believe how much the Stela has spread! The first ones I saw were in Preston up just one side street in around May, then I saw a street in Lancaster lit-up by them. Then around June more and more side streets in Lancaster became fitted with them on a mixture of columns be them concrete or metal. An odd road has them on eight metre-high columns. Over the summer, as has been pointed-out they have begun to appear on the Fylde. When I returned back to Lancaster, at first I thought that all the sidestreet 2600s had been replaced, such was the amount of them! This isn't the case, there still are lots of 2600s, however could it only be a matter of time?! I never thought I'd see the day when the 2600 gets ousted in these parts
For what it's worth I actually like them, both lit and unlit, I agree they do look better on those late 1990s black columns, but look alright on other columns (I even saw one mounted on a fibreglass column the other day!). What I'm not so keen on is how many older lanterns are being replaced, it reminds me of when Lancashires' Beta 79s were mass-replaced in the 90s (could it be that 2600s become just as rare, surely not, this is 2600 country afterall!!) They do seem to be most common in the Lancaster City Council area (only spotted in Lancaster and Morecambe though), I've noticed them in smaller numbers in other areas of Lancashire, however haven't seen many (if any) in the east of the county or in West Lancashire District.
As mentioned by Gramma 6, Vectras continue to be in favour in the Red Rose county with the new remotely controlled sensors being fitted to the lanterns on many main roads. Whilst I applaud Lancs CC for being innovative once again, It's a shame that some roads have now lost their MRL6s (though these remain on many roads), also there's no fun if all the lights come on at the same time!
Having been on a long drive through the east and south of the county at the weekend, I was really pleased to see so many good old SOX lanterns surviving

Lancashire does seem to be a county of two halves lighting-wise; the west of the county (especially the Fylde coast) is mostly SON with SOX lanterns being pretty rare to non existant, whilst the east of the county still has hundreds upon hundreds of SOXs (mostly GR150s, MA50s/60s or 9554s, as well as numerous side road SOX lanterns) along with plenty of SON. Particularly good SOX boroughs are Rossendale, Hyndburn, Pendle and Burnley (many SOXs are on S&L or Petitjean columns too

) Also nice to see is that numerous early SON-ification scheme in town centres and at crossing still remain complete with various Turtle lanterns. Lancaster CC and West Lancashire District Council are exceptions in that they are mostly SON (or increasingly LED) on the side streets, but many of the main roads are still SOX-lit, so are between the two 'halves'.
The Lancashire unitary authorities are complete contrasts when it comes to SOX vs SON as well. Blackburn-with-Darwen has very large numbers of SOX on both its main roads and side streets (SON is common also), whilst Blackpool Borough has all but a handfull (three at the last count, four/five if you include Squires Gate Link Road) with the rest mostly being SON.
Onto your observations about Blackpool's lighting Gramma. I to have noticed the seemingly eclectic mix of lantern (and indeed column) choice lately. I've noticed the ZX2s you mention, I've also spotted one on Faraday Way, one on East Park Drive and one on Clifton Road.
I've seen two Holophanes, one pictured below:
http://paulharris.fotopic.net/p63543533.htmlWhat a strange bracket, usually lanterns on these columns would be installed post top ala the other Holophane, or with a hockeystick bracket! I've also seen on Dickson Road one such hexagonal Stainton fitted with a Stainton Bones bracket and Vectra!
I've seen an Iridium fitted onto a cast-iron swan-neck column, a white ZX2 on a hockeystick and this weired bracket thingy:
http://paulharris.fotopic.net/p63543528.htmlMy theory, the PFI that began in January. Most of these strange occurances happened prior to this, so could it be that the council were just using-up old stock in their depot not wanting to splash out on new lanterns and columns, with the PFI company continuing this practice as a kind-of stopgap until they are ready for purchasing stock? Or perhaps they are trailing different lanterns and columns? I don't think the last one's very likely at all mind.
More information on the PFI:
http://www.blackpool.gov.uk/Services/S-Z/StreetLighting/http://www.clp.uk.com/Blackpool/Template.aspx?function=Home&menuIndex=0I'm following the progress as much as I can, and I have noticed a number of columns are now numbered-up as mentioned on the council website. A couple of examples:
http://paulharris.fotopic.net/p63543530.htmlhttp://paulharris.fotopic.net/p63543532.htmlThe stickers have the council and CLP logos across the top, with installed by E.ON underneath, the column number, the road name, the ward, a message 'Report a street lighting fault', a faultline number and then a web address. The numbering seems to be happening on a ward-by ward basis with the northern and southern wards coming first. Exciting times ahead!