Making new will

One thing I think is important is to specify in your will that any of your DC’s inheritance is passed on to their own DC should one of them die before you.

I have personally seen this happen a few times and have experienced it myself. My single aunt died and left a share to each of her siblings. My DM died before her elder sister, when my aunt died my DM’s share went to my cousins.

I have recently done my will. I have left it equal between my children. I have told them this & given them copies. I think this is fair & simple, avoids any mis understanding.
It is up to them if or how they choose to share this with their children or any future children.

It's up to you, but worth mentioning that on Mumsnet there are frequent threads along the lines of "my DM left a third to me, a third to my brother and the remaining third to be divided between the DGC, but my brother has three children and I have only one - this is so unfair!" or "... the remaining third to be divided between the DGC, but at the time she died I was 8 months pregnant with my first child so she's not being included - this is so unfair!" (It often transpires that the sum in question is about £7.50!! )

The solicitor will explain any pitfalls and word your will to reflect your wishes. If it’s any help bluesaphire our wills also divide some assets into three with one third portion to be divided between however many grandchildren there might be. There isn’t a right way to divide assets, everyone is different and will have their individual preferences. Your solicitor will advise and make sure the outcome is within the law. Please don’t worry, you will find your solicitor will help you through the process.

I think your solicitor will be your best bet for sound advice. Tell them what you want and listen to how they think it ought to be worded.