The Army Boy's Technical School came to Beachley in the 1920's.
After the WWII it became the Army Apprentices School, where junior army recruits (having joined up at age 15/16) would learn a Trade, ie carpentry, electrical, mechanical, survey, etc etc whilst continuing with general education (maths, english etc, encouraged to take O & A levels), and also, of course, learning all the army skills.
At around the age of 18, or after 3 yrs, the 'Boys' would Pass Out of the Apprentices School and go into the Regular Army, having also obtained a City & Guilds or equivalent, in their trade.
Cutbacks shortened their 3 year training as an Army Apprentice to 2 years, and the School became the Army Apprentices College. I believe this was some time in the 1970's - don't quote me on the date, though the information is correct. My father worked there for 30 years as a (civilian) technical lecturer.
In the mid 1990's further cutbacks closed down several of the country's Army Apprentice Colleges, the Beachley site becoming a barracks for the Regular Army.
If you look up BOBA (Beachley Old Boys Association) you may find some archive information, as BOBA is still in existence.
As for its location, Beachley is a couple of miles outside Chepstow, and is on the Gloucestershire side of the river Wye. It sits right at the end of a peninsula jutting out into the Severn Estuary. The (first/old) Severn Bridge crosses directly overhead the barracks.
Since becoming a regular army barracks, it was necessary to build a lot more living quarters, and acres of fabulous playing fields were given over to housing.
