Hi Andrew, we've got a total of 5 in our little clan, 1 who is still in her rather large child seat, 1 who's in a booster seat and 1 who's 13 and almost as tall as me and the missus.
We find the Grand perfectly suited to all our needs. If we're carrying another 2 people, it just means a wee bit shuffling of the seating arrangements.
We put the load cover along the floor in front of the 2nd row of seats when we're not using it. Not ideal I agree, but better than having it lying across folks lap.
Can't say we've ever had the front seats far enough back as to render the rear floor boxes useless - you must be very tall.
I bought the Renault carpet for the boot as I didn't like the colour/finish of the original. It just sits on top of the original. I'm not in the habit of carrying much loose stuff in the boot, but I do find not much moves about on this carpet - I'll dig out the part number if you want it.
We got our car supplied with the "spare" tyre so don't have any experience with the pump and bottle of goo.
I agree they could've put a wee bit more thought into some parts of the design, but I suppose almost everything has to be a comprimise in some way eh ?
All in all we're very happy with our bus