Willowchiff?

Willowchiff?

Observation - Willowchiff? - UK and Ireland. Description: Small lively little bird that has been in or around my garden for over 3 weeks now. I've never seen more than one specimen at any time. I suppose it is a Chiffchaff but it does not look quite right to me.

Small lively little bird that has been in or around my garden for over 3 weeks now. I've never seen more than one specimen at any time. I suppose it is a Chiffchaff but it does not look quite right to me.