What about one of the clam shell type sandboxes. One side is filled with sand and the other side can either be used as a lid (to keep sand clean) or when open filled with water for paddling. We gave one to DS for his first birthday. It is his absolute favourite thing. He spends ages out there every day. We only fill it with water as a special treat on really hot days. The rest of the time it has sand in one half and the "water" side is kept empty and is used as a lid. Works really well. Most of my mother's group friends have daughters and they are all equally enthralled with our sandpit. It would be a definite hit.