Termination of IPDI by exercise of option

I have clients who own a property valued at £700,000 in unequal shares (H 15%, W 85%). In their Wills, they wish to leave their respective shares on life interest to the survivor, but also grant an option to the survivor to buy out the remaining share of the property. The survivor will have up to a year to decide whether or not to exercise the option, and the IPDI will take effect in the meantime. Realistically it will only be W who will be in a position to exercise the option if she is the survivor.

Assuming W is the survivor, am I right in thinking that, if the IPDI in her favour is terminated by W exercising the option, the effect of s53(2) IHTA 1984 is that there is no PET and the price paid by W for the purchase of the share of the propety (£105,000 at the current value of the property) will be out of her estate immediately for IHT (whereas if she were to simply release her life interest to accelerate the interest of the eventual beneficiaries this would be a PET and she would have to survive 7 years before that value was taken out of her estate)?

Thanks

Alison Elwess
Adie Pepperdine Ltd