Last year they had opened admission for Nursery class in January. Keeps visiting their website for details :http://www.thebishopsschool.org/tbsweb/Admission_New/admissionnotice.aspx
Its online process is quite cumbersome, you have to fill online form with specific photo sizes & all documents needs to be in order.
They had asked for :
Bonafide certificate from previous school (if any)
Family pic (father,mother, kid)
Individual pics of father, mother n kid
Id proff of father & mother.
Dnt even give it a try if you stay any farther than 5-7 kms from school. They don't give preferences to children (specially for lower classes like pre-primary) staying far from school.(this is my personal opinion & observation)