It was during the lifetime of James Weller Ladbroke that development on the estate began in earnest. Ladbroke had little personal interest in the development of the estate. He left matters in the hands of his estate surveyor, Thomas Allason, while he concerned himself with country pursuits in West Sussex.
Allason’s lay-out plan required a circular road with large houses along its inner side, a bit like Nash’s Regent’s Park. This wasn’t built. But what we owe to Allason are the estate’s 15 hidden gardens. In most Georgian developments, the houses were built facing gardens at the front. Allason turned this round and provided for the houses to encircle – and back on to - private communal gardens.
Between 1826 and 1831 Ralph Adams, a brick and tile maker from Gray's Inn Road, built houses along Holland Park Avenue. He also set up a brick-manufacturing business to the north-west of the estate in an area which later became known as "the Potteries". In 1824 Robert Cantwell, who later became the Norland estate’s surveyor and designed Royal Crescent, developed land between Ladbroke Grove and Ladbroke Terrace, which he took over from another speculator, Robert Hanson, who had been building houses in Holland Park Avenue.
But before development could start in earnest, there was a financial slump in 1827 and building more or less ceased.