OP, I haven't participated in the poll itself because for all the reasons stated above the options are mute I'm afraid.
We have a savings account in our child's name which we contribute into occasionally; the idea is that it will provide them with 'some' money (it will not be a large amount ant will be nowhere near £20k mentioned).
The child also has an account with a debit card (which they deposit gifts / earnings etc) the idea is that from a relatively young age they get used to the concept of '
If I want it I have to spend my money. If I haven't got the money I can't have it'. You'd be amazed how much they decide they don't want after they realise they need to spend their money on it.
They have a CTF (forerunner of the JISA) which has investments and does have the potential to deliver a significant amount (we / relatives made the account up to £2000 and the investments have done rather well since then). Come age 18 we'll have to hope they are sensible enough to 'deal' with the money.
We have an investment account in my OHs name which we notionally have assigned to the child 'for their benefit', i.e. university, etc. It is this account that we contribute to so that we can assist or even gift some/all when deemed appropriate/required.
Following on from this a grandparent wanted to leave a lump sum to the child but I have discussed this and they have a agreed to leave a smaller amount to the child and leave the rest to be held in trust for the child (to be used for the benefit of the child and any remaining money to become the child's at 25).
There is no one size fits all and I am concerned about children simply 'having money', without the concept of understanding that you have to work for money. There is very much a understanding in the young (very young) of entitlement, something I'm keen to extinguish (as much as possible). You'll never hear the words 'pocket money' in our house. You do tasks, you earn money.
I'll get off my soap box now
Personal Responsibility - Sad but True
Sometimes.... I am like a dog with a bone