For an article with more than 8 named authors, mnras.bst gives "Bloggs J., et al., 2016, ..." but MNRAS style looks to be "Bloggs J. et al., 2016, ...", i.e., no comma between the author's initial and "et al.". This applies to authors of articles and editors of conference proceedings.
It seems this can be fixed by removing the comma in line 474 of mnras.bst.
For an article with more than 8 named authors, mnras.bst gives "Bloggs J., et al., 2016, ..." but MNRAS style looks to be "Bloggs J. et al., 2016, ...", i.e., no comma between the author's initial and "et al.". This applies to authors of articles and editors of conference proceedings.
It seems this can be fixed by removing the comma in line 474 of mnras.bst.