The standing stone in the narrow field next to Upsilon House is one of three stones in Maugersbury now referred to as the Sarsen Stones. The other stones are in the gardens of Upsilon House and Sarsden House.
In 2018 the stone in the field caught the eye of an enthusiastic amateur archaeologist, Andy Waring. During August 2020, between Covid lockdowns, Andy braved one day of scorching sunshine and one day of torrential rain to make an evaluation dig in the field.
Andy produced a comprehensive report here and was keen to return to do further investigations. So, he and two other archaeologists, made a further visit in 2022 and took samples from beneath the stone with the aim to assess the date of the setting of the stone.
The "Palaeo-environmental (charred plant and charcoal) assessment and land snail assessment" by is here.
"Analysis of soil samples with regard to phytolith analysis" can be seen here.
All reports are extremely detailed and very interesting. Very broadly, the conclusion is that the standing stone was erected at a date closely linked with the enclosure of fields and therefore from the 13th centuryAd onwards. This does not exclude the fact that prehistoric activities might have taken place on the site and that the standing stone was moved from a nearby location where it had been part of a prehistoric setting.