I saw these clips for sale by Carjoy in Holland on their website in the past. Something like 6 Euro.
Have had a browse on their site (which has improved dramatically for Murena parts), but can only find the speedo cable at the moment.
Maybe a phone call to them and ask?
http://carjoy.nl/matra-shop/index.php?route=product/category&path=62_146P.S. Donated my last spare recently so can't help on size.
Cheers,
Graham
Just checked with Carjoy:
I have this spring in stock (new original Matra parts).
The price is 15 euro + TAX.
If you need, I make an invoice for you.
Do you need just the spring or the speedo cable too?
Best Regards,
Met vriendelijke groet,
Laszlo Racz