In reply to alexjz:
Plenty of routes are non-tidal. Obvious candidates are Journey To Ixtlan, Aprez Vous, Mercury Direct (there's a higher ledge just below the off-width on the first pitch, non-tidal if the sea isn't too big) Mausoleum: the meat is the top pitch. LH Red Walls can be gained by abseil at any state of the tide whilst RH Red Walls and Vault Wall are accessible in all but the highest seas by using the abseil approach down the L side of the Demerara Wall. Again the C Buttress routes start from a ledge above high tide.
If Gowla doesn't appeal there's always Butter Hole or Pentire both of which have good non-tide dependent routes.