InCarTec produce convertors. Basically 2 part systems, a little loom for the car and one for the head unit, so in your case you need one for the clio and one for a JVC HU. Just checked and the AVX1 is supported by the JVC cable, below are links to the 2 products you need:
HU adapter - http://www.caraudiodirect.co.uk/product_info.php?products_id=3484
and either...
Car adapter
if your car has a dash display - http://www.caraudiodirect.co.uk/product_info.php?products_id=3474
or...
if your car doesn't have a dash display - http://www.caraudiodirect.co.uk/product_info.php?products_id=3473
Hope that helps