Please see below response as dictated by the Acting Archdeacon of St Davids on behalf of Bishop Joanna.
You are now a United Benefice (Parish). The name of this is The United Benefice of Bro Lliedi, you are also the LMA of Bro Lliedi and the Area Deanery of Bro Lliedi. For the purposes of understanding how to refer to your Church within Bro Lliedi I would suggest the Church of St Michaels and All Angels, Dafen within the United Benefice LMA and Deanery of Bro Lliedi.
Holy Trinity becomes known as – the Church of Holy Trinity, Felinfoel within the United Benefice LMA and Deanery of Bro Lliedi