Butlins Minehead has some great castles near by.
Berkeley Castle, Berkeley, Gloucestershire - the oldest continuously-occupied castle in England after the royal residences. Built around 1067, shortly after the Conquest. The present castle has remained within the Berkeley family since they reconstructed it in the 12th century. It is believed to be the scene of the murder of King Edward II in 1327. Restricted opening times from Easter to October, entrance charges apply.
Sherborne Old Castle, Sherborne, Dorset - a ruined 12th-century castle in the grounds of Tudor mansion. During the English Civil War Sherborne was a Royalist stronghold, and following an eleven day siege in 1645, the old castle was left in ruins by Parliamentary forces under the command of General Fairfax. Restricted opening times and entrance charges apply.
Okehampton Castle, Okehampton, Devon - the remains of the largest medieval castle in Devon. Built shortly after the Norman conquest of England, this early motte and bailey type. Used as a fortification until the late 13th century, when its owners the de Courtenays became the Earls of Devon and redeveloped the castle as a luxurious hunting lodge. The castle remained in good condition until Henry VII had Henry Courtenay executed in 1538. Thereafter it was abandoned and gradually fell into ruin, although the central keep still sits proudly atop its motte. Restricted opening times and entrance charges apply.
Nunney Castle, Nunney, Somerset - the remains of late 14th century moated castle, built in the 14th century. Damaged by cannon fire during the English Civil War the castle fell into ruins, although it is still considered by many as "aesthetically the most impressive castle in Somerset." Free and open access at any reasonable time.
Nether Stowey Castle (Stowey), Somerset - built in the 11th century, the earthwork remains of this motte and bailey castle once boasted a 10 m square stone and timber keep atop its substantial earthen defences. Possibly as act of revenge following the Second Cornish Uprising of 1497, where thousands of West Country rebels marched on London, the castle was laid waste. Free and open access.
Farleigh Hungerford Castle, Hungerford, Somerset - the remains of 14th century castle. Built 1377 and 1383, the castle was constructed as a simple rectangular building with curtain wall. At the outbreak of the English Civil War in 1642, the castle was held by Sir Edward Hungerford, a leader of Parliamentary forces in Wiltshire. The castle escaped slighting as a consequence of this. The last of the Hungerfords to hold the castle, another Sir Edward, was forced to sell the property in 1686 in order to settle his gambling debts. By the 18th century the uninhabited castle had fallen into disrepair. Restricted opening times and entrance charges apply.