Just received a message from someone with experience of central asian races who says that the Lesser Whitethroat mentioned in the previous post "looks very good for Steppe Lesser Whitethroat [Sylvia curruca halimodendri - also known as Central Asian Lesser Whitethroat]. Quite sandy-grey looking contrasting with greyer hood, whiter throat and dirty buff underparts. Probably Steppe Lesser Whitethroat will be found to be a regular late autumn visitor to the UK in some years, like this year, once they sort out the systematics. It is also a potential split."
Here is another pic of the bird. Feel free to comment!