You can either remove your existing chuck and replace it with that one (after removing the SDS adaptor) or else chust clamp the SDS-spigot-with-chuck in your current chuck - as it it were a drill - and fire away. Jobbie jobbed. In two ways. I think...
I see your suggestion DA is a 1/2 UNF thread, but I suspect that a 10mm chuck would have a 3/8 thread. aSDS adaptor should fit in a 10mm chuck.
I'm going by the OP saying he currently has a keyless Bosch and that this chuck is advertised as being for "Makita, Dewalt Bosch drills". So I am assuming that this chuck will be a straight-froward replacement for his own, so problem theoretically solved. But he doesn't even have to do that - he can simply slip this fella into his existing chuck using the SDS spigot wot comes with it. Or am I missing something?
Ooooh - I beg to differ "I see your suggestion DA is a 1/2 UNF thread, but I suspect that a 10mm chuck would have a 3/8 thread..." - is that not suggesting that the chuck fittings could have different threads, so this new chuck won't fit his drill?
So in the end followed chippies advice. Bought a new chuck and swapped it over. Seems a bit big for the drill but does the job. Swapped back over after. Job done.