Starter Fuse - where on earth is it?

Our XV 2016 has sat in the driveway for a while and the battery has run down. We recharged it but it still won't start (it has one of those autostart/stop buttons). We called out the AA and the mechanic who eventually turned up (apparently the AA subcontract out to localish garages) tried connecting a new battery but it just made a dull whirr when pressing the start/stop button. Cradling a live battery in his arms, he then lowered it onto the dead one in the car and there was a huge shower of sparks. I'm no expert but I don't think this has helped. He then poked around in the fuse box under the bonnet and said the fuse had gone. He then left saying he couldn't do any more. The next day, we separately arranged for a breakdown truck to tow the car away but the guy said as there wasn't any puff at all in it, the steering lock was on and he can't move it. So now it sits on the driveway and we are stuck. I've tried to look at the fuses but can't tell which one controls the starter motor (if that is even a thing). If it is, does anyone know which fuse it is and if they are available at somewhere like Halfords? Sorry to go on but we are well and truly stuck at the moment. Thanks in advance. 🙂