Vent plastic turnbuckles

Lost a couple of the catches securing external winter vents. Discovered they may be called "plastic turnbuckles"
Anyone know where they can be sourced for my Ravenna? 

PLOUGHLIN wrote:Lots of places sell them.

https://www.ebay.co.uk/itm/171716061034?chn=ps&_ul=GB&_trkparms=ispr%3D1&amdata=enc%3A1Rdfc5WZgRD6yzA7EV4re3g31&norover=1&mkevt=1&mkrid=710-166974-033325-9&mkcid=2&mkscid=101&itemid=171716061034&targetid=2211795017455&device=c&mktype=pla&googleloc=9050375&poi=&campaignid=20641216497&mkgroupid=158412477550&rlsatarget=pla-2211795017455&abcId=9325620&merchantid=7331084&gclid=CjwKCAiAzJOtBhALEiwAtwj8tp3iWR0NP2fi18bKFWRFUiAXbNBDUnx8hMamgx0oiQ6ma-CB7MRCAhoCpvsQAvD_BwE

https://www.google.co.uk/search?q=fridge+vent+cover+catches