Jamo,
The seats were brand new and hadn't had anything applied to them, unknown or otherwise. I have since tried to recover the leather on one of the seats using an off-the-shelf water based leather cleaner, but it has had no effect. The car had only covered a couple of hundred miles before the trip to Le Mans.
At the moment, I'm not suggesting Kirkham do anything, but I would like to know what the cause of the problem is. As both Jeff and you have said, simply getting wet shouldn't be a problem as the leather should recover once dried out.
Here are a couple of pictures of the driver's seat.
It looks like just a salt mark in the pictures, but the leather has taken on a thick, crusty effect and the leather below the mark has a different texture to that above it.
I love my Kirkham and I'm very proud of it, so please understand that this enquiry isn't in any way a finger pointing exercise at KMS.
Thanks,
Paul