Rear Brake Pedal Travel -- Speed bleed nipple thread size?

The rear brake pedal on my 2014 1200LC GS always seems to have a long pedal travel with very little braking power. The dealer bleeded the brakes and it was ok for a while but then seems to return to the same state. Looking on forums suggest that it is a common problem and bleeding the brake needs doing regularly.

For this reason Im thinking of changing the bleed nipple to a speed bleeder nipple.

Does anyone know the thread size for the rear brake bleed nipple? I think its 10mm x 1mm but not 100% sure.

Thanks

Ian

Any help video below he says the sizes.

Thanks video shows rear M10x1