right, after there seems no equivalent reader and the firmware is available, I gave it another shot.
This unit is perfect (screen alignment, uniformity of backlight) and of the second batch, however, this too has the battery drain in sleep mode and discharges over night.
I contacted Kobo support who responded with
"Thank you for contacting Rakuten Kobo Customer Care and reporting about battery life on their Aura One eReader issue, a release to address this will be available sometime in November."
Awaiting more details but I'm pretty frustrated by now
