I have seen good availability of the BP-SCL5 batteries, recently, from such sources as B&H, Adorama, and Leica Store Miami. Briefly, Leica Store Miami showed out-of-stock, but, by yesterday (March 16th) the BP-SCL5 was again in-stock. Not feeling desperate, I had wanted to wait until April to buy more BP-SCL5 batteries, in order to avoid accruing a month of interest on the credit card, but as soon as Leica Store Miami showed out-of-stock, I quickly ordered a pair of them from Adorama, just in case the importer-/distributor-level pipeline was starting to run dry.
A recent you-tube presentation indicated that Leica has found a new manufacturer for their cameras' batteries. VARTA, in Indonesia, has been the manufacturer of all of my Leica BP-SCL5 and BP-SCL2 batteries that I have used, thus far, and is also on the label of the two batteries I just received.