Belvelly Castle, Fota, Co Cork, €375,000
If these ancient structures are the toys of rich men, this one even comes with a set of instructions. Inston didn't really get past the starting post at Belvelly but the architect did manage to come up with a comprehensive plan as to how the 13th-century structure could be turned into a comfortable three-bedroom residence, however, and he will make the drawings and specs available to any purchaser.

Inston reckons it would cost between €250,000 and €350,000 to do a basic refurbishment.

The castle guards the strait between Fota Island and Great Island at the entrance to Cork Harbour, and it is relatively close to the city and airport.

The 80ft tower is in a relatively good state of repair given its age and status as a defensive battlement. Sir Walter Raleigh is the best known occupant.

Collier Jackson-Stops, 01 6333700, www.colliersjs.com