Hi Marcus,
don't know if you'll see this in time, but here's my tuppence worth anyway!
If the sea's rough, then your chances of the Surf Scoter are pretty slim, and the high tide at Bowling Green is probably your best bet - the wet weather means a good chance of the Long-Billed Dowitcher showing well, plus 400 odd Avocet and lots of other stuff, often very close. If its not rough, then at the high tide the Surf Scoter may be surprisingly close in [ groynes 10 - 13 are the last 4 groynes you reach walking out along the warren ], when I saw it, it was off groyne 13, and close enough to spot with the naked eye. The estuary on the inland side also has good birds at high tide, though most'll move out of comfy bin range, you do get the odd wader come right up to the pools in front of the hide. There's also plenty to look at in the interior of the warren.