Where property appropriated to a NRBDT in favour of the surviving spouse increase in value, could the increase give rise to IHT charges for the trust?

If we appropriate the deceased’s half share in a property to a NRBDT more than 2 years after the date of death for the benefit of the surviving spouse, who will continue living in the property, and the property increases in value during the spouse’s period of occupation, I understand that PPR will be available to the trust and CGT will not be payable on any gain. If the gain increases the value of the trust’s share to more than £325,000, however, will this then give rise to IHT anniversary and exit charges? If so, are there any alternatives (e.g. equitable charge) which would avoid these charges?