Bookcases (Whitchurch SY13)

I'm trying to help my elderly dad bring some order to his home. It's hard to get him to throw anything out so I'm focusing first on organizing. He has lots of books, on tables, in boxes, on the floor...putting them on bookcases would really help. So I'm looking for any kind of bookcases, the bigger the better, solid to take the weight but don't have to be cosmetically good because I can sand and fill and paint.
Many thanks