There is an article in the 1989 MCSA Journal called A Pride of Lions, written by Peter De Tolly. This covers all the better routes on the Clifton side of the peak. There are some long classics, most noteably Clifton Crest and Aquanaut and grades to suit all climbers. There are very few available RD's for the other areas but a much earlier article in the Journals contains some vague photo-topo's.
There are over 70 routes on the sandstone ranging from single pitch routes to 7 pitch long routes. I am in the process of writing a guide to all the routes on Lion's Head (both Granite and Sandstone) which should encompass over 100 routes. I am hoping to have it out in the early part of next year.
If you are interested I would be happy to show you some of the areas not covered by Peter de Tolly's article. Feel free to contact me at firstname.lastname@example.org