Geoff,
This may be a silly idea, but could Justmatz not purchase an Executive Mat Set from their local Reno dealer and use these as their pattern/prototype? I just had a set supplied by my dealer under warranty for my 2002 172 (my original drivers side was holed after 400 miles). As they were a slightly lighter colour than the original, they supplied a full set. (4). They are a dark grey thick pile finish with velour heelpad (Clio logo and button/spikes on drivers side only). They are listed as 77 01 416 257 in the March 2002 accessories catalogue. I found them to fit perfectly. I think they cost £47. Im sure Justmatz will soon recoupe on this investment and can probably sell the Reno ones on anyway! Ditto for all the other Clio models if Reno replacement mats are still available. Cannon also do tailored mats for most models from Halfords.