Garden Birds: PURPLE SANDPIER and SIBERIAN CHIFFCHAFF (Slimbridge WWT 9/11/13 sightings)

I went to Slimbridge as yesterday I received some exciting news. A 1st winter purple sandpiper had been found feeding extremely close to the observatory on the Rushy and was later roosted there as well. Luckily my monthly Slimbridge club is on the 2nd Saturday of the month so I was able to have a look if I could see this rare wader. They usually winter on the East and South coasts of Britain but a very small wintering population (2-7) winter down at Battery Point, Somerset. I Gloucestershire, the closest we get is one which is usually found at Severn beach. For Slimbridge this is the 4th site record so this makes it even more special.
A Siberian chiffchaff was also sighted there today with a Scandinavian chiffchaff and the normal race which we get in Britain showing extremely well on the decoy boardwalk and from the Eco garden which was very nice to see. This would be my first confirmed record of this species as on a walk which I did in the Spring in Berkeley saw a look a like of the bird which I saw today. They are surprisingly tame and feed a bit on the ground so watching this bird fly around was very nice.
There was an American green winged teal but I decided not to look for it.
Firstly, I didn't have my binoculars.
Secondly they look identical to the European teal except from the American green winged teal has a vertical white stripe going down it's body.
Thirdly, there was 1500 teal, a garganey and this 1st winter American green winged teal meaning it would littrally be impossible to spot.