A low tide count for the Non-estuarine Waterbird Survey (NEWS) resulted in:
Black-headed Gull (116); Carrion Crow (75); Great Black-backed Gull (5); Grey Plover (1); Herring Gull (382); Lesser Black-backed Gull (1); Meadow Pipit (1); Oystercatcher (15); Redshank (2); Ringed Plover (15); Sanderling (2) and Turnstone (2).
Wader numbers low, but surprised to see so many crows using the beach. A 1CY Herring Gull continually rising and dropping a whelk on the rocks before being robbed by an Oystercatcher was noteworthy too.
There’s still a few vacant sectors along our coast if you’d like to take part in this survey. See link above.
Glamorgan Bird Club 
I think you missed a number of birds. At high tide at Newton Point over Christmas I had 9 Purple Sandpipers, 11 Grey Plover, 30 Ringed Plover. At low tide in the bay: 30+ Sanderling, a few Dunlin, 10+ Curlew, and higher numbers of Turnstone, Grey Plover and Redshank.
However JWD this was a low tide survey count on a specific date and the same birds aren’t necessarily there all the time. I find the same with my WeBS counts and low tide counts at the Rhymney Estuary.