Thermostat rubber hose / bung thing . . . ???

Hey,

I'm after a spare rubber bung which fits on top of the thermostat, mine is leaking coolant.

Here is a link to a pic of it;

http://www.rsmegane.com/attachment.php?attachmentid=1608&d=1413731504

Let me know as car is currently out of use.

Thanks,

Rich