Rear Brake Master Cylinder Seals

Hi Guys. Ok found fluid weeping from the dust seal on the bottom of the rear brake master cylinder, I’ve looked on Motorworks for a seal kit but can’t locate anything. Does this mean the rear Brembo cylinder is non-rebuildable? or are seals available elsewhere??
Thanks again.

I had the same problem and couldn't source a seal kit or a new master cylinder anywhere. I bought a used one from Sherlocks, been fine ever since.