Velocepress is reprinting a Brooklands manual for the Mercedes 230 line. It has some very good illustrations that are not in the BBB or Haynes manual. The photos look to be from the BBB, and unfortunately are pretty dark. But I think it is worth buying just for the clear illustrations of the heater controls!
On a side note, Velocepress does "Print on Demand" publishing which may be just the thing for that SL113 Restoration Manual that some of you are working on.
Pete S.