haha doogs beat me to it Dome Hill is NW of The Guardians.
Rumour has it you need to descend off the Western end of The Guardians(apparently there is a cairn at the top of the gully) and then sidle under the cliffs to reach Horizontal Hill etc, obviously quite scrubby and cliffy, PM details if you do it, I have considered this route previously

EDIT: Should add I've also heard of a party that descended off the NW edge and sidled a long way due to not being able to find a safe route to the west.