Google is your friend:
HISTORY
Westcott Venture Park is a former WWII airfield used to train the crews that went on to fly the legendary Lancaster bomber.
RAF Westcott opened in September 1942 with crews using Wellington bombers for training.
Many of these crews saw active service in Lancaster bombers in the fierce aerial campaign waged by Bomber Command over occupied Europe.
The RAF moved out in August 1945 shortly after welcoming nearly 53,000 liberated POW’s who were flown into Westcott in Operation Exodus.
In April 1946 the base reopened as the Guided Projectile Establishment, involved in the research and development of rockets. High-tech business continues at Westcott to this day in the field of satellite research and development.
I found a more detailed history through Google some time ago (I live near there and was curious too) but it did not come up through Bing when I searched just now.
Blue skies.