Tax on Children's Savings in Spain

[coopster]

My wife and I are thinking about moving to Spain permanently. My children have Junior ISAs that I understand become taxable once they become spanish residents. Do children have their own income tax allowance in Spain (like in the UK), or is the interest they earn added to their parents' income for tax purposes? Also, are there Junior ISA equivalents in Spain that may be money tax efficent for them?
Thanks