We have many here in Wales. South Wales and Noth Wales are areas to head for for decent castles. Anyone wants more details...
The eastern part of South Wales are Chepstow, Caerphilly, Castell Coch, Cardiff Castle etc...
The middle parts of South Wales.. Examples are Woebley, Kidwelly, Llanstephan (f), Laugharne, Drysllwyn (f), Dinevwr, Carreg Cennen (Children need to be on a lead or have their hands held for Carreg Cennen. Sheer unguarded and unfenced drop) are a few examples.
south West Wales. Pembroke (You have to see Pembroke!), Carew, Manorbier, Llawaden (f), Kilgerran (Sometimes spelt Cilgerran), are all nice castles worth the visit.
North Wales. Caernarfon (Another must see!), Conwy, Harlech, Criccieth... And many more!
(f) = free entry.