Ah I’m only seeing this now!
Happy to go into more detail.
We’re outside Lisburn where there are two preps which are attached to respective grammars- Friends and Wallace.
As other pp’s have pointed out, we don’t have many “true” independent schools in NI- I think Rockport is the only one.
I went through the grammar system myself, and from what I see of the senior school that the kid’s prep is attached to, it can offer similar facilities etc as what you’d be paying for in GB at an independent.
The preps do tend to be clustered around Belfast/Lisburn/Bangor though- there is less of an appetite for them outside of the cities, I think due to the very good public provision.
If private schooling is important to you, along with coastal living, you could look at Sullivan Prep, Regent House or the previously mentioned Rockport which are in North Down, which is a nice part of the country.