Hello Ody,
interesting bird. First impression to me was "its an easy Willow Warbler" of those grey and white eastern ssp.. Everything looks good for this, head pattern, leg colour, jizz. But this bird has a short PP, but even after a second look, I couldnt convince me, that this is a Chiffchaff.
So what is it? Its not a Marsh Warbler: head pattern is wrong, as is jizz (at least for me). Its not a Sylvia Warbler, I see a Phylloscopus, so a late moulting local Willow Warbler? Because, apart from the PP, this bird looks so good for a Willow Warbler, including appearent bright orange legs (or is this due to strong back light, making them paler and brighter than reality?) and extensive pale lower mandible.
Conclusion? More pictures, please! I have for example no experience with Booted Warbler, but even after a third looks it looks good for Willow Warbler.
I know, leg colour is variable in Chiffchaff. But this bird hasnt just pale legs, but the colour looks spot on for Willow. So do the pictures shows the real colours?