Ballyscullion Park is a private property mainly used for weddings and other events. I sent a private message to the owner of the park (I was too desperate hahaha). The owner, Rosalind and the staff who assisted us, Jonathan, were both very nice and accommodating.
LOCATION: 61 Ballyscullion Rd, Bellaghy, Magherafelt BT45 8NA
Season 3 Episode 2: “Dark Wings, Dark Words”
This location is where Arya, Gendry and Hotpie are discovered by a small party led by Thoros of Myr, who suspects them of having escaped Harrenhal. He tells them that he and his men fight for the Brotherhood without Banners, and takes them to an inn to eat.