This is a Grade II listed building - see https://historicengland.org.uk/listing/the-list/list-entry/1295836 - from the listing: "...Mid/late 17th Cent elaborately restored 1879 to design of Lady Marion Alford and her son Earl Brownlow..... Deeds of 1698 and called Halfe-Moon Cottage in 1726."
One of several buildings in Frithesden that are listed.