Hi Julian,
Indeed you can acchieve what you want, but it is better to define a command
which takes care of the number and the title of the chapter at the same time
(as in \ myChapterCommand below).
%% begin example.tex
\definefiller[ChapterRule]
[alternative=rule,
color=gray,
Have achieved a Chapter title with rules either side (see below - not an
original invention!) but I want the chapter number to be part of 'My
Chapter Title'; instead, the following MWE means it comes before the
ChapterLeftRule. I know I can do it by actually putting the number
before My
