They were financed by Lord Howard de Waldron of Chirk Castle and presented to the 9th Battalion RWF. Supposedly based on a medieval Welsh sword pattern: the hinged hilt guard was officially patented. Within the battalion they were issued to machine-gunners and possibly other specialists such as bombers. Some blades are engraved "Dros Urddas Cymru" (For The Honour Of Wales).
Another who may have used one was A.O.Vaughan (aka "Owen Roscomyl"), a writer and adventurer who spent time as a cowboy in the American West and fought in the Boer War, before raising the Welsh Horse in 1914. His biographer Bryn Owen found tantalisingly little about his WW1 service even though he rose to Lieut-Colonel rank (in the Northumberland Fusiliers). He turns up briefly in a Welsh-language autobiography by E.Beynon Davies, an officer of the 19th (Bantams) RWF, where he's described as giving bloodthirsty advice to the troops and carrying an unusual short sword. He actually signed one month of the unit War Diary in 1916 as acting CO, so it wasn't a mistake on Davies' part. He was best friends with de Waldron and a Welsh nationalist, so it's not unlikely he got one.