IHT allowance for non domicile and non resident spouse

Hi, my spouse's status is 'non domicile' and 'non resident' in the UK for the treatment of income tax and CGT. However, I have read that he can write to HMRC to ELECT to be 'UK domicile' for the purpose of inheritance tax? Can you confirm this please? And if so, which HMRC department does he write to? Thank you for your help.

Hi,
We can only provide general information / guidance in this forum.  
For an answer to a question of this nature, you would need to contact our inheritance tax helpline on 0300 123 1072 or write to
Inheritance Tax
HM Revenue and Customs
BX9 1HT
United Kingdom.  
Please have a look at guidance at:- Inheritance Tax: detailed information and Inheritance Tax Manual
Thank you.