It is possible that Louisa's birth was not registered - not compulsory until the 1870's.
Under the 1836 Registration Act, Section XVIII,
registration was compulsory in the case of the Registrar. The onus was on him to collect births and deaths. In carrying out his duties the parents were compelled, under the Act, Section XX, to supply the information when asked.
A penalty not exceeding £2 was introduced in Section 39 of the 1874 Registration of Births & Deaths Act, for “failing to give information concerning the birth…….. as required by the said Acts”. There was also a penalty for late registration in the 1874 Act, as in the 1836 Act.
Stan
Stan