Grandparent wills.Have you done this?

My will is very simple. All my estate to be divided five ways between my five children. I have put in a caveat, that forty grand be held back to be given to each of my eight g.children on reaching their 25th birthdays. This money to be look after by my two eldest children. If any of my g.children have turned that age before I die, then they would receive that money immediately.
I do hope that I may be around to see the older four g.,children approach this age, but no way will I with the four youngest. Just be nice for them to have something to remember me by as they reach proper adulthood.

I agree that more information is needed, I don't think there is such a thing as a 'grandparent will'. I will however share what we have done (through a solicitor):

After we both die, our 'estate' is split in 2 - half goes to our children (if any die before us, then to their partner)
Half goes to our grandchildren, this is set up as a very simple trust:
The trustees are our own children - this keeps costs down, they can charge expenses (including legal if needed to the Trust).
The Trust ends when the youngest grandchild turns 25. Although there is a theoretical possibility of more arriving, this is a simple way of allowing the money to be available to the grandchildren without making it too complicated.

The trustees, knowing what money is available (approximately) release each grandchild their share (minus a bit) when they turn 25. Some can be released before they are 25, for purposes the Trustees agree on - we gave examples of education, buying tools for a trade, a house deposit etc.
When the youngest is 25, the Trust ends, and a final distribution is made.

In our family, where some of our children are parents and some are unlikely to be, it seemed fair. It also means that the grandchildren get their money directly. Grandchildren mean full or adopted grandchildren, we would amend our will if a any 'steps' needed to be considered.

It does need tying up legally, but for such a simple trust it is neither too expensive nor complicated.

That isn't the case in England. You are, more or less, entitled to leave your money as you please. Intestacy rules only kick in if you haven't made a will or the one you have made is judged to be invalid. The most common reason for this is that people forget to make a new will after they remarry.

You need advice from a solicitor who specialises in will writing.

Check out the rules and regs around trust funds. It's a complicated area with some costs to consider.

I don't understand what you are asking more information needed.