The two "exotic" sources Nash et al identify as possible sources for sarsen at Stonehenge are Stoney Wish near Ditchling Sussex and on the side of the A272 near Bramdean in Hampshire.
To help identify them here they are:
There is a question mark over where the Bramdean stones originated as the circle of stones seems to date from about 1845 - https://pastrambles.wordpress.com/2015/02/22/the-bramdean-circle-of-stones/ erected by "Colonel George Greenwood of Brockwood (formerly Brookwood) House, a large property down the lane on the other side of the crossroads...there are two possible explanations of the Colonel’s motivation for building the it in 1845 or thereabouts: “One…is that he wished to see how long it would be before they were regarded as relics of the ancient past – this is commonly said of them today. The alternative is that they were a demonstration of the power of his tree-lifter”. The tree-lifter was the Colonel’s invention for transplanting trees up to 30 feet in height with their ball of earth intact, a feat the apparatus apparently made possible for a single individual to do at a rate of one tree per day. The somewhat aptly-named Colonel Greenwood was very enthusiastic about the importance of trees to the landscape and wrote a book in 1844 called The Tree-lifter, Or a new method of transplanting forest trees,....Colonel Greenwood is said to have excavated local archaeological sites and was a keen geologist referred to as ‘the father of subaerialism’, ascribing the greater inequalities in the earth’s surface to atmospheric influences. ..It was said in his obituary that “had he fallen amongst geologists in early life, instead of amongst ‘thoroughbreds’, he would doubtless have occupied a leading place among men of science”. ... Incidentally, the colonel is buried nearby at All Saints church, Hinton Ampner, his grave stone a recumbent sarsen which stands out pleasingly amongst all the more traditional ones. "