Update: To get the between subject main effect I have found that you can do:
ranova(rm,'WithinModel','Week');
The thing that doesn't make sense is why the F value for the within subject factor 'Week' (labelled I think as '(Intercept):Week' in the ranova output) differs from the example I cited. I have run the example in SPSS and using the 'anova_rm' function from the file exchange both of which give me the same F value as the example from youtube (https://www.youtube.com/watch?v=JBoHHFvVsqw). Here is the code to do this ANOVA using the anova_rm function:
dataTable2 = table2array(dataTable);
[p, table] = anova_rm({dataTable2(1:6,1:3) dataTable2(7:12,1:3)});