Hi there been reading through possible reasons for this but unsure. I've had a soaking wet floorwell for weeks  Over the last few years of owning the car the antifreeze in expansion tank has been virtually on minimum but it was fine.  In summer it lost a fraction of water so light came in dash. I topped up a little and since then no problems. Soon after had water on footwell but I don't think it's too with that I put k seal in just in case I think the leak was coming from sunroof