Have you tried the Caravan Breakers in Blaenavon? I know you need an Awning pole,not a caravan bit, but they might be able to help. Also Frontier Leisure near Crumlin have spare poles and stuff in their shop. They sell most of their stuff on-line too.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.