Robartes acquired about 7 acres (2.8 ha) of land across the Cross Deep Road opposite the house, extending west to the line of present-day Radnor Road, and which he connected to the riverside property by a tunnel like his celebrated neighbour to the north, Alexander Pope.

[1] Some observers conjecture that Walpole was piqued by his neighbour's anticipation of his own architectural ambitions, as this pre-dated his gothic embellishment of Strawberry Hill House.

[2] Radnor House's riverside gardens to the east included part of Cross Deep Ait, a former larger neighbour of adjacent Swan Island.

A footbridge connected the island, metal remnants of which can still be perceived lining the central footpath in the gardens today.

Following his bankruptcy in 1779 and death in 1781 there followed a period of uncertainty about its ownership due to disputes over title resulting from Hindley's debts.