Is this a IPDI to satisfy RNRB?

Good Morning,

I am acting for a beneficiary who has been diagnosed with terminal cancer. She has weeks to live.

She is a beneficiary under her mother’s Will and set to inherit circa £300k. Her mother’s estate required the RNRB and this was claimed.

She has instructed me in a DOV to redirect her share of the estate to her children subject to them attaining the age of 30. They are both currently over 18.

Is it correct that provided i draft the DOV so that the gift is vested at 30 and section 31 is not excluded then this will be a IPDI and the RNRB will not be affected?

Many thanks