Replacement gym ball plug/stooper

Hi folks,
was wondering if someone could help me? A few months ago I moved house and deflated my gym ball. I put the plug/ stopper in a "safe" place, but after much searching cannot find it!
I am trying to buy a replacement stopper online, managed to find one £2.72.. but the postage and packaging bring the total price up to £15.72!
Does anyone know where I could get one? Or if anyone has a defunct gym ball (e.g. burst) could they spare the stopper? Of course willing to pay any postage.

Many thanks,
Fonz

If you have a nose on ebay, a lot of gym balls are going for 99p plus postage, so you might be better just buying another one...either keep the new one or just buy it for the plug/stopper. There's one on there at the mo, 99p with £2 postage, finishes tomorrow. Just search for "gym ball" and then "ending soonest".