Depends upon the facts.
Presumably the lifetime election is designed to mitigate the IHT charge on the earlier death of a UK domiciled spouse by taking advantage of the unrestricted inter-spouse exemption.
Form IHT 205 may be used where the spouse's estate qualifies as an excepted estate otherwise IHT 400 needs to be completed.
It is therefore necessary to ascertain if any of the conditions for an excepted estate are satisfied.
The election needs to be made in writing to HMRC; there is no need to supply it with the IHT 205 or 400; indeed the election may not have been made at the time the form is submitted.
yes it is to mitigate iht. Estate is a bit over the 325k limit but the property can be redirected to children via dov. However the purpose of the domicile election was to take advantage of the unrestricted spouse exemption.
you say there is no need to send the election letter at the same time as the iht forms, but if this is not done aren't hmrc going to send a big iht bill to the non domn spouse?