It's straightforward to achieve what you want to happen. Speak to a solicitor who has experience of doing wills.
Assuming that your home is your major asset then it is likely that they will suggest that you own the property as tenants in common. What this means is that you each own 50% of the house instead of owning the whole house jointly between you.
Your will leaves your 50% share of the house to your DD but your DH is given a life interest to live in the house until he dies or some other event happens (eg you may choose to also include if he starts to cohabit or marry another person as a trigger to ending the trust).
In the same way, DH leaves his 50% of the house to DD and DSD and gives you a life interest to live in the house.
When you have both passed away that leaves your DD with 75% of the house and DSD with 25%.
"my parents are clear they want their money to go to me then DD. How do I ring fence that?"
I don't really see the point of doing that unless they don't want to give the money to their grandchild while she is still in her twenties. The simplest way is just to name your DD as beneficiary.
Any money that they give you directly then becomes your money and you can do what you like with it. If they want to give money to you and also to ensure that your DD gets some then they should put both of you down as beneficiaries in their will. Otherwise you can do exactly what you want with the money and cannot be forced to pass on any of that money to your DD against your wishes.
If it is a substantial amount of money from your parents that may cause you to go over the inheritance tax threshold yourself when you eventually pass away then it would probably be better to pass as much as possible on directly to your DD rather than to you.
If they are insistent on you having some control over the money then one way may be to do a discretionary trust. In this case the money is left to your DD but you are the trustee and get to decide what money to give her and when.
There can be extra inheritance tax charges for this type of trust so it may anyway be better to just name your DD as a beneficiary.
These are the sort of things that the solicitor will likely go over in detail.