So I want to use "Sior" in a genitive formation, and I'm unsure if the following name should be in the genitive or not:
Sir John's House : Tigh Sior Seán or Tigh Sior Sheáin
I was thinking the first is more correct, based on other titles and apposition...
Lord John's House : Tigh an Tiarna Seán
Brother John's Hough : Tigh an Bhráthar Seán
The only real example I can seem to find is:
Sir Harry's Mall : Meal Sior Anraí
But of course, Anraí's genitive is the same, so... (put I presume this is still nom.)
Just wanted to get yer thoughts

I don't think "sior" sounds very natural in Irish.

Genitives confuse me
Without the "tiarna" it would be Tigh Sheáin. How that changes when Tiarna is added I don't know.

teach/tigh an Tiarna Seán (acc. to CO genitive/apposition rules)