[GreggWardNZ]

When I measure the voltage between the Vcc and Gnd, at the base of the FS1000A, I only ever see around 0.57V. I have checked the soldering around the joints of the FS1000A and have resoldered, but still it does not work.

The GND at the FS1000 is commuted by the 2N7000 transistor, so with a multimeter, you only can see brief pulses.

To check if the 2N7000 transistor is working, you can follow this procedure:

Connect a voltmeter between GND (not the FS1000A gnd point) and the Arduino digital pin 7. At each 5 seconds you should see brief pulses of voltage (they are too short to get a reading, but this doesn't matter), now connect the voltmeter between the VCC and GND points at the FS1000A module. You should see the same pulses.
If you don't see the voltage pulses, the 2N7000 transistor is not working.
If you see the voltage pulses, and the TX Led is not blinking, the LED is faulty or reversed.

Thank you very much for your help. I will try and have a look at this over the next couple of days.

Gregg