Happy to report it’s all working on my bench.
The £43 I spent on the sig generator was well worth it. It allows me to create an ASK (digital AM) signal using an external input to modulate. Using an arduino, I wrote a small program to write at 2400 baud to the serial port. Using this as input to sig gen and putting the output of the sig gen into a small wire wrapped around the coil and onto a small load resistor, after some fiddling it all works beautifully !
I sure learnt a lot following the signal through the circuit.
I did find an error in the circuit, in the original circuit as I uploaded, the output was inverted. Swopping pin 2&3 (2nd stage opamp) corrected that.
Again, thanks for all your help, I could not have got this done without your explanation and helping my calculations which were, ahem, dodgy to say the least.
Correct circuit attached (and next time I will draw from left to right 
I’ll post when I get this off the breadboard and stuck onto the meter to see if it all really does work
Alan
