Isn't it nice when somewhere far exceeds expectations! I have an old, but still usable Parrot SK4000 Bluetooth kit on one of my helmets. It's still working but I thought I'd see if I could install a new battery. Contacted Parrot and the reply was:
"Thank you for contacting Parrot.
The SK4000 has been discontinued for some years now, as a result spares are not available to order. When available the battery was not obtainable as a spare.
I have looked around and found a demo unit that has not been used, the main part we nickname the puck that fits on the helmet, you are welcome to have this as a goodwill gesture.
Please provide a postal address and I will post this out to you.
Kind Regards------ "