It's been ages since I posted any updates. The reason being a change of job now means I'm getting the train to work and the S4 is just sitting. The sensible thing to do would be to sell it but I don't really want to part with it. I've been trying to take it out every couple of weeks to stop it seizing up. So tonight I pop out and am surprised to see the coming home lights don't come on. The car starts first time but the radio is also off which is odd, I don't turn it off. Realistically it's been sitting for 3 weeks and it's been cold. I assume the battery has got low and some kind of self preservation / power save has kicked in as identically described here: https://www.audizine.com/forum/showthread.php/685786-2011-S4-Power-Saving-Mode Following a run out everything was back to normal. I doubt the battery is dying at 4 1/2 years old but will keep an eye on it. Fortunately I have a 50 mile trip tomorrow so should charge things up.