Culdrose will take on hosting the exercies (sic) as well as providing QRA in the time of emergancies (sic)
Quite apart from the weather factor (one of the worst in the UK, surely?), I think Culdrose would struggle somewhat to host major exercises for two reasons: the much shorter runway than St Mawgan, and the lack of free dispersal areas - unlike the enormous areas at St M, which have had to cope with all of 3 helicopters in residence for the last 15 years, Culdrose is more or less full with a great many FAA units, both FW and RW.