Helping out here: it is the Karosserie-Fabrik Friedrich Radochla.
Thank you! I must've stared at that thing for close to an hour, seeing RadBehla, RadBehld and a bunch of other stuff that made no sense at all (RadBchla, RadBchld, Radßehla, Radßehld, Radßchla, Radßchld, and so on). My brain never registered the fourth letter as an 'O'.