Thanks for all your inputs there. I have attached the source file and another file with, as best I can make out, a diagram of the nearest components.
According to the source file, the circuit was used to locate the proximity of LC tags. It used swept frequency TX and measured the amplitude of the signal to determine the distance of the LC tag to the search coil - one of the coils in the bridge. The sweep was approx 100 to 400 kHz. The proximity of the LC tag drew down on the search coil providing a difference between the input signal and the signal on the search coil.
Unfortunately the source file is not clear so a little hard to determine values and notation.
I have prototyped my circuit up to the push pull amplifier, but am interested to know what part the 2 polarized caps and +12V input play as my prototype has an RF application.
Thanks