One of the questions asks whether parents observe "the laws of family purity". This alludes to a couple's abstention from sexual relations for seven days after a women's period, and her use of a mikveh to purify herself.
In his report, the OSA adjudicator said that it was not unreasonable to ask the question, but that it was impossible for a rabbi to "objectively assess whether or not a family observes the laws of family purity".
The adjudicator found that other criteria on assessing observance also did not meet the OSA's requirements to be clear, objective and fair.
The school, in Hendon, north-west London, has until February to make the amendments.