Same as normal Dave, anti-clockwise, have you flattened the tabs that are on the retaining washer sat behind the nut, screwdriver usually prises the away, then tap the hammer on end of screwdriver to flatten them proper, if nut is being a pig try a long tube over the spanner to give you more leverage, or an ratchet/impact driver if you can find one to borrow for an hour or two.
