I don’t know! That is to say I don’t know where the bird at the Warren is from. With some moult contrast in the tail (some very worn tail feathers with inverted ‘V’ or broken tips) and rather worn brownish wings, it has an overall ‘scruffiness’ to remiges and rectrices which suggests a first summer bird. And with very little real colour below, just some warmer peachy wash on breast sides and flanks. It’s clearly a female. There is no definition of a white moustachial stripe. In the field it does look quite strongly cold blue-grey at times with rather blueish- grey over the head and lower back and rump with more obviously soft brown zone across the mantle. I didn’t hear and call. It’s not likely to be Moltoni’s Warbler as young bird have complete winter moult and would have newer fresher plumage. So is it a Western or an Eastern Subalpine? Right now: don’t know!