Thanks for the replies everyone. I've got diagnostics check booked in for the 11th August so will report back with their findings!

On a slightly different note, Hyundai informed me they delivered the N Line and not the N Line S....I think I'll be negotiating a smaller rental fee

Oh really? Surely when the car is locked then all lights/infotainment/screens are shut down and nothing would drain the battery? I'm completely dumbfounded by this...

Oh good, that's reassuring. I'll try and find that thread. Yeah I don't really want to be returning the vehicle...waiting to hear back from my lease company

Hi I received my car on the 25th and all was fine and dandy until the a few days later when I couldn't unlock the car with the key fob! I managed to gain manual entry and but was unable to start the car! The battery was completely drained! I called AA out and they jump started it but couldn't figure...