Willow Warbler (Phylloscopus trochilus)

Thinking Willow warbler or Chiffchaff - didn't hear it sing (which is the easiest way to differentiate between them) - Have posted in bird group to ask for ID, will update if I get a definitive answer.

After expert in bird ID confirmed it as Willow Warbler (Phylloscopus trochilus) I have amended the title.