Ian,

Quite rightly, you blame the melt down of the tuner not to the tuner's
intrinsic inefficiency (which none of them have) but to the abuse inflicted
on it by the user with the help of a transmitter.

All tuners are high-efficiency devices when operated within their ratings.
They can't help being otherwise. They have only a length of wire in the form
of a coil and a condenser.
---
Reg.