Who bought it?
The article doesn't specifically say who purchased Moelwyn:
"It was purchased in February 1925 for use on the Festiniog and Welsh Highland Railways though Honeywell Brothers- the agents he had dealt with for the Simplex - at what seemed to be a bargain £248 13s 4d. Put to work shunting at Minffordd and together with the Simplex it was used for a short time to replace horse traction on part of the Croesor Tramway." (My italics)
I'm assuming it was Colonel Stephens, as he is mentioned in the rest of the article.