Mentioned in “The Ancient Stones of Wales” by Chris Barber and John Godfrey Williams (1989 Blorenge Books):
“Crossfoot Standing Stone in a field adjoining the road from Clyro to Newchurch near Crossfoot. ... R.C.A.M. No. 13 of Radnor describes it as 6 feet high but it is in fact less than 5 feet in height.”
Ironically Coflein gives it as “c.2.0m high”.
coflein.gov.uk/en/site/306305/details/CROSSFOOT+FARM%2C+STONE/