So far i have personally confirmed the following parts to be suitable as replacements:
Battery:
Yuasa 12N9-3A-1 -
Perfect size wise/exact replacement.
The included bolts are a little too wide, and some ring cutting may be required.
CCA rating of 80 is somewhat low.
Yuasa YB9L-A2 -
Much like the battery mention above, but with a higher CCA rating.
CCA rating of 124.
Yuasa YB10L-A2 -
The BEST possible replacement confirmed so far.
CCA rating of 160.
Dimensions are larger than that of the batteries mentioned above, but fit has been confirmed perfect (no modifications are necessary atleast on the 125SM - and SX presumably - )
Please feel free to add your own experiences with compatible parts.