The question must be are you buying the land or a hill fort, just ripe for restoration. No it is a scheduled monument....
http://www.lodgeandthomas.co.uk/Property/Caer-Bran-Sancreed-Penzance--23-acres-land-inc-Iron-Age-Hill-Fort.aspx
"Viewing at any reasonable time" :)
Hopefully a heritage group will buy it, it really is just the fort isn't it? Although preferably not EH unless they promise not to build any tunnels or visitor centres.
Guide price?