Whilst researching to find our MX5 NC, we saw quite a few that were for sale and in the photos was one showing the inside of the boot with a black plastic tray type liner for the recessed area in the floor of the boot.
Cannot seem to find one for sale anywhere.
Does anyone know where they are sold and how much please ?
Boot liner mx5 mk3/3.5/3.75 mx5parts.co.uk £68.95. You may get one cheaper from local mazda dealer
Part number NE85-V9-540
Looking at that part number, I’ve just realised that the boot liner which came with my recently purchased NC is actually an ND liner. I had idly wondered why it was this shape 
although it does seem to fit OK.
Now - do I buy the correct NC mat and try to flog the ND one, or do I just live with it?
To be honest it covers more of the boot floor than the correct NC one does, I’d keep it and then transfer it to your ND when you buy one🤭
Not that we spend hours looking in the boot mind.
But as you have asked, flog it and get the correct one that fits and looks good. 
