Android Tablet (Wallisdown BH11)

Hi everyone. I'm currently looking for any basic, unwanted tablet for my son. It doesn't need to be any particular size or anything special. It also doesn't have to be fast. Even if the battery doesn't last, it will probably do fine for his needs. My son Josh has learning difficulties, and has been given a special Mathematics app by school that he is absolutely loving and learning so much faster with. It works on his phone, but it's just that bit too small. He literally needs something bigger than a phone that he can leave plugged in with the app at his desk at home, dedicated to that one app for the next couple of years The app will run on most tablets, even older ones apparently as it's very light. If you have anything redundant, we would love to give it a go before I have to spend on something overkill that he really doesn't need. Many thanks. Lucy x