I think Gransnet can be useful in pointing people in the right direction, making suggestions, and helping people work out what they need to ask a solicitor. What we say here isn't a substitute for legal advice, but by sharing our own actual experiences, we can help each other know what to expect and what questions to ask.
I do know that when you make a will, you can say what is to happen to a beneficiary's share if that person dies before you do (e.g. if your daughter predeceases you, her share of your estate shall pass to her children). But if you die first, then once the money has been passed on to that daughter, you can't dictate what she allowed to do with it or who should inherit it from her -she might just spend it all!