Having seen the Marlborough Downs Pollisher and also the examples in Nantes Museum and Vannes Museum those stones look a lot like each other (apart from scale, but the actual pollishing areas are similar in size). This does not strike me, immediately, as a pollishing stone, as has been said, the marks are very narrow and, from a practical perspective, do not look like axe pollishing grooves.
Which leaves them being either plough marks or some other kind of rock art, something I am much less well versed in...