Sorry, it's a 2011. Think my wife has noticed this even after a short run.
Don't think it is the relay as there was still enough in battery to turn engine a little (and fan was not running) one one occasion, so not running battery down completely, more like a slow drain.
Have had load test on battery - ok
I can test for drain myself, but what are the common faults for draining battery, have heard of bluetooth module faults?