Hello,
Congratulations on your granddaughter!
Has your daughter opened a child trust fund for her? Once such a fund is open, it's very easy for friends and family to pay funds in as often as they like.
It's understandable if you'd prefer to keep your savings for her in a seperate account, so it can be a gift just from you - but there are some great benefits to a trust fund.
Otherwise, perhaps you could ask your daughter to open a seperate account at her local branch of your bank and then give you the details so you can regularly pay in.
Frustratingly, many children's accounts don't pay great rates, so the trust fund route could make the most difference to her future.
Hope this helps,
Felicity