"Forgive me for being under illusion this is an aviation site and therefore most people would be familiar with aviation terms,"
He may not be British, he /she may be under 50 years old, they may not be involved with maintenance of complex or military aircraft aircraft. If you hire your plane by the hour, or operate it under a big maintenance organisation (a very large airline for example) you may have no idea of what "anti-det" is or was.