This is from Chelmsford County High school's admission policy:
Only one address can be used for application. In applying these admission
arrangements ‘permanent home address’ will be defined at the permanent place of
residence of the parent with whom the pupil spends the majority of the school week
(Sunday to Thursday nights inclusive) at the date of application. This address must
also normally be the address to which Child Benefit is paid. Permanent residency is
defined as owner occupancy or long-term letting contract of a residential property
where child benefit and occupied community charge is paid (evidence will be
In the case of a recent change of address, additional evidence will be required in the
form of evidence of exchange of contracts or a signed tenancy agreement. This is in
addition to the child benefit statement and evidence of occupied community charge.
Families whose first home is outside the catchment area and/or who are only living
in short-term rented property (12 months or under) or temporarily with friends or
relatives in the area will not qualify to be considered as resident at that address.
Proof of residence can be requested at any time throughout the admissions process. If
it is subsequently discovered that an application contains a falsely claimed or dated
address, then any offer of a place will be withdrawn.
The student must be able to show to the school’s satisfaction that she has a right to
reside in the United Kingdom and is entitled to State Education. Overseas applicants
must hold a full British or EU passport.
Hope this helps.