I think you will find that International Aeradio Ltd (IAL) was started by BOAC, perhaps even Imperial Airways, I don't know the exact date.
It became a subsidiary of British Airways, having originally been owned by BOAC to provide ground services at various staging posts across the world and, in turn, Aerad was part of IAL. Prior to that time, IAL provided. or had provided, ATS at many locations world-wide - the West Indies, Libya, West Africa, East Africa, the Far East and notably the Middle East (Bahrein, Abu Dhabi, Dubai, Sharjah etc) - and also at a number of small units in the UK, then just around that time (70s and 80s) adding contracts at Liverpool, Bournemouth and Southend Airports and the Brent Field HFIS in the North Sea.
BA later sold IAL down the river to BT who conducted an asset-stripping exercise and then sold the company on to Serco, whence it became Serco-IAL. As I understand it, Bailbrook College continued successfully until Serco overstretched themselves in their bid to get their sticky paws on NATS at the time of PPP and they were obliged to sell the family silver to make up their losses.