Aliens of Brecon wasn’t the first Torchwood story I wrote. The first was Bad Nights, which I wrote a few days after the first two TV episodes had aired and Not The Man From Atlantis which I did about a week later. Aliens of Brecon was my idea for getting the team out of Cardiff, and I had just completed it when Small Worlds aired, including a teaser for countryside, which was set in the lowlands of the Brecon Beacons. It is a completely different story, of course, but some of the issues about town people camping in the countryside seem to have been mirrored in it.
There is something of a similar plot in that people were being taken up the mountain to be eaten. In Countrycide the monsters turned out to be Human beings, which happens all too often. It was something of a Welsh version of Texas Chainsaw Massacre. My aliens turned out to be a slightly more humanoid version of the brain eating Arachnoids in Starship Troopers. What both stories prove is that there isn’t very much new in fiction.
Sending Ianto on a different mission, looking after Beth, was intended to introduce a new relationship for him that was a healing process after Lisa, the Cyberwoman, but the character of Beth wasn’t particularly well received. She didn’t seem special enough for a Torchwood character’s girlfriend and she was quietly dropped in subsequent stories, only to return, in Rear Window, to become the Torchwood secretary, a role which seemed to suit much better.