Alan I'm glad your still looking!...(off the top of my head) for c20 years I can recall some of the birds found by numerous birders in the Lee Valley Essex/Herts/Middx.reservoirs,..Phalaropes (one guy found three RNP's during this period) also Skuas (all 4), Sabines, Little Auk, Leache's petrel, Fulmar, Gannet, Manx Shearwater, Snow Bunting, Twite, Hoopoe etc. also found in the valley 3 Ortolan's and a Barred Warbler(together same field), Red-rumped Swallow, Marsh Sandpiper, Paddyfield Warbler, Subalpine Warbler etc. It may be something to do with ''fly-lines'' (ie hitting the East coast, then the Wash and heading South, through the Ouse washes and then the Lee valley before hitting the Thames?...pure speculation at this end (and not mine).
Find some reservoirs, old sewage farms (are there any left?) small isolated copses at the top of a hill, Set-aside fields, Industrial/marshland, gravel pits etc....and when you find the ''biggie'' invite a few friends over.![]()
The Lee valley has a good area of gravel pits ,South Warwickshire has Marsh farm ( now decimated ). I have spent the last 25 years driving around south Warwicks and have to agree with Alan that it is not a good birding area.
Within 10 miles of Straford I can recall American wigeon ,Great white egret , Aquatic warbler and Dotterel. Some of these are from sites now spoilt.