Asset tracker v2 - serial1.available()

I’ve had an Assettracker v2 for some time and its been working with my set of code OK - recently though i updated the firmware to to the latest release version - this seems to have stopped the GPS from working very well.
So i have downgraded the device back to 0.7.0 but serial1.available() is never > 0.

I’m currently testing with some basic code from rickkas7:

Serial1.available() is always returning 0

Running the asset tracker with a CR2032 battery + external antenna.
GPS red led is flashing away and its in a position it used to get GPS from.
Its plugged into my PC via the USB and has the lipo plugged in.

So have i somehow damaged the board? or is there anything else i could do to try and get round this.