Hi again,
I think it is definitely a Warbler rather than a Chiff Chaff as the main difference between them is the colour of their legs. Willow Warblers are brownish and Chiff Chaffs are black. If you look at the photo on ....
http://www.grayimages.co.uk/Chiff%20...2003,04,05.htm
you will see how black the Chiff Chaf legs are. from what I can see the two photos on this thread aren't as dark as those.
Marie.