Discretionary Trust and RNRB

I have a new estate and on reading the will it puts into a discretionary trust “the maximum amount of assets which can be given at death without any liability being incurred for the payment of IHT” Bit summarised but that’s the gist.

Husband surviving but in care and there are three grown up children – who I think intend to appoint out all to themselves in due course as husband does not need.

Am I correct that the discretionary trust will not only include the NRB of £325,00 (bit less than that as some lifetime gifts to knock off) but also the RNRB due to the wording?? Estate total £640000 inc ½ share of house at £312000 (exc lifetime gifts).

If above is correct then presume cant do IHT205 as can’t claim RNRB allowance that way and would be over tax levels. But added problem is that under the will the ½ house would pass into discretionary trust fund (if assumption above is correct) so on that basis can’t claim RNRB until appointed out to the children at a later date. Does this mean that the family would have to pay IHT on that portion and claim back within 2 years of death when appoint out?? Would it be best to appoint out the property element before probate then to avoid paying the IHT in the first place?

Any help would be appreciated!

Daniele Marks
Chambers Fletcher