 From age 16 a child can register to be their own contact and this registration cannot normally be reversed.Except in that case and adoptive parents registering, the previous registered contact will be contacted to obtain their consent to a change of contact.There are restrictions on investing in ISAs in each tax year (6 April to the following 5 April) which affect the type of ISA that may be opened and the cumulative amount of investment during the course of that year.