The cockpit of the Gnat to which the OP refers has been butchered into bearing scant resemblance to any RAF Gnat...
The Gnat's OR946 instrument display and general characteristics made it an excellent lead-in trainer for the Lightning, although students would first have to complete their weapons course on the Hunter.
Hawk was intended to replace both Gnat and Hunter but had few, if any, swept-wing characteristics. But as a trainer it has served the RAF well - even though it lacks the Gnat's soul.