/ Ropes for Cornwall
I normally climb off a single rope 60m mammut (normally on grit or limestone).
I know I'll need a rope to absail in to some routes on, which i'd need to leave in place in case of hasty escape. (I've got an old 30m that will do) Are 1/2 ropes essential for some routes or will a doubled 60m do? (maybe even a 1/2 and my single)
You're unlikely to need an abseil rope for the classic Severes etc, though a tide timetable will be handy for some of them.
A doubled 60 will be fine for the usual easy routes. Most of them were done in the days when one belayed every time one ran across a ledge.
depends which venues you go to, Bosigran and Sennen (amongst others) do not need an ab rope, but many do.
I think at VS and above half ropes would be useful but not essential (I'm not sure I'd say half ropes are ever essential). In general they are more useful than say on grit and less useful than limestone.