Right of Occupation for daughter in Will, work round IHT possible?

Situation:

Father died leaving RoO for spinster daughter. Property valued at £475K. Total estate was £740K so some of RNRB used.

There is also a son with his own family. Brother and sister have a good relationship.

Daughter lived with her father for most of her life, unlikely she will leave. Issue is with aggregation for IHT. Daughter’s own estate approx. £200k.

Other than transferring house in equal shares absolutely between brother and sister (CGT issues for brother, security for sister), not sure what else I could do. Any suggestions greatly received.

Karl Taylor
Parker Rhodes Hickmotts