Car will tick over but will not rev, its just like the throttle cable has snapped. But it is fly by wire so any ideas where I should start.

think you will need the codes read before going any further,
try unplugging the maf sensor at the air filter, some cars limp if this is faulty, other wise is the fuel filter ok? but i would expect rough running rather than no revs at all

Plug it in, check for faults codes, look at live data for throttle pedal and throttle body position.