Given the good run of wading birds at Dowrog Common this autumn, this article on the Wildlife Trust of South & West Wales website is worth a read to understand the work that is being done there:
https://www.welshwildlife.org/blog/nathan-walton/transition-mire-enhancement-project-dowrog-common
David's Broad Haven gull is a Great Black-backed Gull, which explains the bulky bill and legs :-)