It really should be.I'm not 100% sure the downstairs ring (which I assume is where the qualified person would take the feed from) is RCD protected,
No it isn't, I'm afraid.however even if it is I'd rather have a seperate RCD on the outdoor socket simply because that's more likely to trip (for example when the hedge cutters go through their cable)
Plus hedgecutters have 2-core cables, so unless the severed end comes into contact with an earth then no RCD will trip.