Sometimes I get "Gearbox Fault", "DSC not available" and "Park Brake fault" come up as key switched on. If I cycle the auto gear lever these faults disappear but still will not start. OBD scanner records FAULT:00, PEND:02 These are shown as U0121 Lost communications with ABS control module & U0073 Control module communication bus off (generic) I have disconnected the battery overnight and charged fully but all is still the same

Hi

These are common and usually caused by a low battery

have you checked the battery voltage, should be above 12.5 volts, if the voltage is lower than this battery may need replacing

also sometimes these faults caused by a low battery will need reseting with jaguar IDS/SDD before they will clear

Ideally you need to get it plugged in to see what faults are listed, generic code readers will only read and clear engine codes, not gearbox, dsc or epb faults,

I'd check battery voltage and make sure it does not drop rapidly, you have to wait 40 mins before the car sleeps and the current drop to about 30mA

also diesels seem put strain on alternators and these can fail,  causeing a short, making the battery voltage drop quick

cheers

Joe