Sorry. I had expected and intended to respond yesterday. I know ILR often has a spare photo or two up a sleeve so thought an extra one would be helpful before I wrote my once or twice a year theory about darkish legs with orangeyish feet. The "I took this a while ago" also had me thinking back a few years to an i.d. where a subsequent photo flipped it from one species to another. (not ILR one). WW arrive in UK later than CC as a rule (though obviously both are here now and have been for a little while). Not sure what I was thinking though as it's unlike me to hesitate!
Anyway, I agree re willow warbler, not least face is more like typical ww than cc. The legs and feet combo is the bit I wanted to type yesterday. I still have yet to see a chiffchaff with pale legs/feet. I know they exist but every photo showing pale feet, I want to see something that says it's a chiffchaff....and I've yet to see any photo do that. There are a lot of ww's with dark legs......and a huge number of those have pale feet like this individual.