No - Trinovante is widely accepted as meaning New Troy. The Belgae occupied what is now Gloucestershire, parts or Somerset and Wiltshire. They were very recent arrivals and clearly related to the Germanic tribe that gave its name to Belgium
A study of Iron Age tribal names and their origins could tell us a great deal about Iron Age Britain. Unfortunately the only written records are by the Romans who saw the Ancient Brits in much the same way we saw the natives of India during the British Raj.