While we were in Oxford at the weekend, we went to the "Romance of the Middle Ages" exhibition at the Bodleian Library (of course!) It had a manuscript page from The Two Towers - and the original manuscript of Gawain and the Green Knight - and lots of other wonderful things. But possibly best of all, it had the Tolkien / Gordon edition of Gawain, annotated by CS Lewis! There's a picture here:
http://medievalromance.bodleian.ox.ac ... wain_and_the_Green_Knight

- wellinghall