Hello I am a solicitor with over 15 years experience. I will try to help you with this.
My initial reaction is that the Dutch lawyer is right and you can do the will in either jurisdiction.
I will check this later as I am away from the resources I need to be certain of this.
Will you send an email?
I will reply in this forum.
When can I expect a reply?
You were gong to check this yesterday evening. Do you have any further information?