Help needed please - plugs for end of synop aero bars?

[fab at forty]

Just wondering if anyone can help at all - the bung/plug has fallen out of the end of my Synop aero bars and I am having no luck at all sourcing a replacement. I have gone into several LBS and none have anything that fits flush with the end of the bar and I'm worried I'm not going to be allowed to race either without one, or with a poorly fitting one.

I've also emailed a couple of online stores, but does anyone either know for certain where i could get one (I only need one!) or have any more ideas....

I would be extremely grateful for any helpful suggestions

f@f