So I thought I'd treat the Brommie to one of the specifically-designed-to-fit-under-the Brompton's-saddle 2017 from my LBS - who also happened to supply the Brompton.
It is much lauded (by Brompton) for allowing you to fully drop the seat tube without removing the light.
Got it home to find the bag contained one light, one USB lead (I'd have preferred it if the light had a USB tab under a rubber cap - like my Leyzene KTVs do, which if you lose the cap, the light remains functional. Lose the lead and the light works not so much), and a hole.
A hole through which the bracket had made good its escape
So back to the LBS, this time I saw their mechanic - the same guy who PD my Brommie.
I pointed out the bag had been opened and the bracket was missing.
He scrabbled around in the drawer and produced a bracket, bought it over and fumbled round under my saddle with the words 'Only it won't fit this saddle, you need the 2017 saddle'.
I groaned as my saddle is hardly worn from once a weekly, or even less frequently, shopping trip, so I was reluctant to replace it.
Mechanic went over to the wall, pulled the saddle off the hook, ripped off its packing card and gave it to me FOC
How this saddle differs is that it has an M5 threaded insert moulded ino it's base, and that is what the bracket screws onto - if only they had given me an M5 bolt!!!
Those of you who know me will know that an absence of an M5 bolt is not really an issue in my house. And I'll bet the one that comes from Cat-Eye isn't stainless.
So the light is pretty bright, and has more modes than you could wish for.
I've no idea of run time.
I've already said I would've preferred it to have a capped USB tab rather than a loseable lead.
The bracket will also take other Cat-Eye lights - such as the LD600 - the staple of my other bikes.
Which makes me wonder whether the bracket is available on its own - probably not, as I'm sure they'd like you to pony up the £20.00 for the light.
I don't remember reading in any of the reviews or in Brompton's blurb that it'd only work with this year's saddle.
Tl;dr?
Brompton specific rear USB Cat-Eye does pretty much as it says on the tin.
Someone has been playing it lite with saddle information.
Chris Compton's after sales service rocks.