I think that depends which schools you put on the form, some require additional information. If I recall correctly Bennet Memorial require a letter from your vicar detailing the extent of your godliness.
Best to check the schools you choose in the admissions handbook (you should have been sent on before the whole process started) I think the details for each school are there.
DaddyOh - unless this has changed this year, there is no requirement at Bennett to detail your 'Godliness'. You only need to fill in the supplement form which is a box to tick and a vicar signature which is an agreement with the box category you have ticked.