Following a post on the Treherbert page, I contacted Fernhill Farm who were promoting a new venture with Glamping pods. I suggested they considered expanding their market by offering overnight stops for Motorhomes. I have had 2 positive replies , and they are considering trialling an Aire facility with water and waste facilities.
The location is mideast for the new Tower ZipWorld attraction as well as walking , mountain and road biking,
https://www.fernhillvalleyfarm.co.uk/