Isn’t the jury still out on whether it is actually a good idea to start a junior ISA?
Most children won’t actually pay tax on their interest anyway as they won’t earn enough.
Plus as its an ISA you have effectively given the money to your children so when they turn 18 its legally theirs to do what they want with it. Whether that is a sensible contribution to uni fees or drugs and booze!
A standard savings account/investment may be better for a one off lump sum compared to the ISA which would be better if you could max it every year.
Money saving expert explains: http://www.moneysavingexpert.com/savings/junior-isa