In 1937 Kenneth Castle became Headmaster of Lea House School, a small day prep school in Harpenden with about 15 boys (and a few girls!).
1n 1943 Capt K B Castle (as he was then known) was elected to the IAPS (Incorporated Association of Preparatory Schools) as Head of Lea House.
In 1947 Mary Kincaid joined the staff of Lea House and later that year she and Kenneth Castle announced their engagement. The purchase of Aldwickbury mansion and its 14-acre estate was in the process of negotiation after Mr Castle, who had seen the potential of Aldwickbury as a day and boarding school had invited Brian Chidell, who joined the permanent staff of Lea House in 1946, to become his junior partner. Brian Chidell had previously worked at the School as a Junior Master before going to university and serving in the army.
Aldwickbury Ltd was incorporated in 1947 (Company no. 453745) with Mr Castle holding two- thirds of the shares and Mr Chidell one-third.
In April 1948 Mr Castle and Miss Kincaid were married and moved into Aldwickbury mansion. Some 70 boys and 7 staff moved into their new premises from Lea House at the start of the summer term with Mr Castle as Headmaster and Mr Chidell as his deputy.
The first Aldwickbury magazine of May 1949 gives a hint of the challenges that had to be faced in that first year:
‘There is something to be proud of in being one year old, and to have confounded the gloomy prophets who foretold that disaster would overcome us if we moved to such large premises in these difficult days.
‘We feel justified in looking back over the year with some satisfaction in that we have not only survived, but made Aldwickbury very much more suitable for use as a school by means of various internal and external alterations, maintained and increased the number and efficiency of Day Boys, and started the Boarding side of the School with 18 boys.’
With just one boarder at the very beginning in 1948, the boarding side grew to a total of 52 boarders by September 1957, which the magazine of July 1958 refers to as ‘Capacity load’. Up until 1960, Mrs Mary Castle personally supervised the domestic arrangements and catering and oversaw the boarding department where matron cared for the boys’ needs. The 1958 magazine reports: ‘The buildings and grounds have been slowly and steadily improved, furniture and equipment of all kinds have been gradually obtained, and we feel that now after a decade, we have converted an old-fashioned private house into a reasonably modern and well-equipped school.’