Could be Vega as suggested by Paul but difficult to suggest anything for sure from the images without date and open wing view, any more images.
Both Slaty-backed (which is darker than Vega and Mongolian, but apparently some are paler close to some Vega). Vega and Mongolian has wide white tetial crescents. P10 seems to be not fully grown. Vega is a late moulter - Mongolian and Slaty-backed usually little earlier, variable though. Although variable and depending on time of year,head streaking usually rather heavy and continues down the breast in both Vega and Slaty-backed (wirh dark around the eye as a "black eye") usually faint in Mongolian, and concentrated to the neck area. Pale eye seen in all although some Vega have dark eyes, darkish looking in some Mongolian.
Thanks Paul and JanJ. Images were taken 20th Jan. I have a few other images but are very similar to those attached. Head/neck streaking is clear which suggested Slaty-backed in winter plumage to me...but then I'm far from a larid expert!