The earthworks on Freezing Hill are quite visible from afar – they seem to defend the steep south west slope of the flattish topped hill. The ‘Magic’ record is not yet online, so doesn’t come up with any details to confirm a prehistoric date, but there is a barrow (at least on the map) above the north western slope.
According to Mark Richards’ “The Cotswold Way” (1984) the earthwork is called ‘eald dic’ in a Saxon charter (so one assumes it is pre-Saxon if they thought it was old). He suggests ‘freezing hill’ comes from ‘Frisian’s Hill’ – Frisa being a OE nickname. Moss speculates it may come from ‘Frey(a)’:
https://www.themodernantiquarian.com/post/31851
Isaac Taylor raised its status on his 1777 map of Gloucestershire, on which he labelled it ‘Royal Camp’.
George Witts (c1882) gives ‘Furzen Hill’ as an alternative name (which is quite a boring explanation) but could be based on local pronunciation of freezing? And I’m sure it is freezing up there at the moment.
A prehistoric sandstone axe was found here at some time, as you can read at
https://ads.ahds.ac.uk/catalogue/search/fr.cfm?rcn=SGLOSSMR-SG2428&CFID=392636&CFTOKEN=45832204