As far as I know, the Richbrook are just standard aerials which screw in place.. but, they have a grub screw so you cant just "unscrew them"..
I dont see how it works 100% tho, cus the grub screw can only secure the screw into the aerial, but it also screws into the base? So I dont see how it stops you taking the whole arial including the grub screw..
Not sure.. heh.