Chiffchaff in Scotland (1 Viewer)

[ScottishBirder]

Wondering if anyone has a thought about this Chiffchaff which was singing a different song. I heard this call and couldn’t figure out what it was. It then popped out calling. Looks like a standard Chiffchaff but doesn’t sound like one. More flutey and drawn out call. By the time I got my phone out it stopped. Any thoughts appreciated. This was at Torness power station in East Lothian.

 

[Butty]

Another (jolly nice) photo showing the primary-tips would be good, but, short of that, looks fine for a chiffchaff (singing an unusual song).