The filter on the 1.6 is also used by some models of the Peugeot 305, 1.3 litre petrol I think as well as the 304 coupe and convertible. The last one I bought came from
www.mister-auto.co.uk their product code is BOL-B031328 but when I checked today they were out of stock. On the filter housing of my car there is a part reference EL 1958. Googling this bring up a couple of French suppliers who can supply them. It is a Mecafilter product and the part is still listed in their current catalogue
http://www.mecafilter.com/catalogue/index.php?cat=1-2-3-4&marque=674&modele=2061&sousmodele=2584&vehicule=77829 Hope this helps, but in answer to your original question, I would be interested in a bespoke product if one can be produced at a reasonable price, otherwise why not pick up a load in France next time you're there?