On 28 September 1854, Macnamara married Lady Sophia Hare, daughter of the local MP for St Albans the 2nd, Earl of Listowel.
After building grandiose lodges and clearing and preparing the moated site, he seemed to abandon the idea, probably due to lack of funds.
As Billington became the estate village, Macnamara began to build a manor house, which was a large, multi-gabled Victorian mansion.
A row of cottages existed within sight of the new drive, although as the landlord, Macnamara turned out the elderly occupants and placed them in the workhouse.
It was said that when he encountered any of his tenants driving sheep or cattle along the road, he ordered his coachman not to stop or slow down.
An underground suite of rooms was furnished at Billington Manor, where he would retreat for long periods of time at the slightest threat of thunder.
Arthur Macnamara was buried in the Billington churchyard, with a monumental tombstone surrounded by iron railings.