I have added another link to some of items from the Bodleian Library, these are probably from the exhibition next year.
If you looking to get an Alan Lee signed Trade Beren and Lúthien for the UK list price, £20, then another UK source is Goldsboro books, Waterstones are out of stock.
https://www.goldsborobooks.com/product/beren-and-luthien/
https://www.goldsborobooks.com/product/beren-and-luthien/