Wookey hole definitely only means female genitalia.
The cave park by that name is just the owners having a dirty joke at the expense of the general public who have to hear young children and parents saying that phrase outright and inappropriately in public.
Another miss used word is 'pussy'. I feel so uncomfortable hearing my mother constantly telling my cat that he is a ''naughty pussy''.
''I sexed my girlfriend in her big, hairy wookey hole''
Father : My wife is going to show the kids around the wookey hole this weekend.
Father's mate: What the cave park?
Father : No, her pussy
Father mate: Oh! ... can I bring my kids too
Father : Sure
''Apparently it is cheaper buying tickets to go inside a wookey hole if you buy them off street rather than through an agency''