To answer this question, it is easier to consider Key stage 4 qualifications as a whole.
In Year 11 nearly all of the qualifications available to your child at Woodhey High School are GCSE qualifications. For most subjects these are taken at either Foundation Level (where grades C to G are available) or Higher Level (where grades A*-D are available). All grades from G upwards are classified as a pass. You will often hear people talk of a grade C and above as a 'good pass'