I just came across this Youtube video submitted by modern day exponent of the collodion process, Quinn Jacobson (http://www.studioq.com/). Seems there is quite a vibrant collodion subculture in Europe and the US. There are lost of fascinating videos on Youtube about collodion processes and artists.
It gives you a real appreciation of the skills involved and the difficulties faced by Merlin and Bayliss (and the many other photographers in the field using wet plates - the American Civil War photgraphers spring to mind here). I can just picture them cramped in the darkroom wagon, trying to keep the dust out of everything, while they floated the emulsion onto the glass plates.