Right to Occupy vs Life Interest vs Discretionary Trust

I am currently drafting a Will and need some guidance.

The testator (divorced) has 3 children from a previous relationship and currently lives with his partner with whom he has a young child. The testator solely owns the main residence worth £700k. His partner also has 3 children from a previous relationship. The testator would like to ensure his partner and young child are looked after if he deceases but he ultimately wants the capital to go to his children only and not his partner or her children.

My understanding is that there would be double inheritance taxation if a life interest or right to occupy was given to his partner. Would a Will directing his estate into a discretionary trust be more suitable? What is the best way to preserve the RNRB?

Many thanks

Ravi Solanki
Strathmore Wills & Estate Planning