You said on Mine-Explorer you needed the driver to work with 8.4v this driver will only work up to 4.5v
Yes Mr Ogof, AMC 7135 chips according to the data sheet are OK up to 6V, however whether or not this includes the polarity protection diode is unclear. My comfort zone with these is up to 5V.
Beware of using a driver intended for SSC P7 or Cree MCE as they often output 3 amps which is very iffy territory for the XML, again read the data sheet and you will see why.
The drivers I use for XMLs have circuits on both side as I need a very low form factor, so these would be useless to you which is why I didn't offer one.
The one that DX has in a suitable voltage range (57779) has something of high form factor as well as outputting an excessive current. This could be changed by fitting different loop back resistors but would require expert soldering skills
You also get a strobe mode which is OK if you want it but most people dont.
I have no personal experience of this product so can only go from description and user feedback
My avatar is a poor likeness.