Purple Heron eludes this observer

A look over the Carlton Marshes Scrape initially revealed a fine Wood Sandpiper, 5 Ruff, a Dunlin and when joined by Ian he did well to spot a superb Little Stint next to the Dunlin that suddenly appeared from nowhere. Even better he found my lost Zeiss eyepiece nearby saving me a lot of trouble and expense in sending the bins back to the Zeiss factory- you don't expect things to fall off top of the range binoculars! No sign at all of the Purple Heron, although 5 Snipe flew south over the scrape. Also later 2 Barn Owls were hunting by the dykes. I walked back to the car park and scanning Whitecast marshes for 1/2 I saw a lady and gent peering intently onto the scrape with bins. The cycled back and the lady said the Purple Heron (& she was adamant it was definitely the Purple Heron & I believe her) had just flown back onto the Scrape 8.30pm. She said it was walking around in the water with 2 Grey Herons, I ran back and got there 5 minutes later at 8.50pm, I could only make out 2 definite Grey Herons, (I couldn't see any other Herons) I also saw 5 Egyptian Geese and ducks and waders in the gathering gloom but it was too dark to see anything else, this was extremely frustrating, when I had been there looking cover the Scrape until 8pm!