Lock need Circlip/ E Clip for Honda Genuine Top Box What size

Can anyone tell me what size of Circlip/E Clip fits Honda Genuine Top Box Lock
Where could I get just a few as it seems you can only buy bulk

Funnily enough, i just had to replace my Honda top Box lock. Having just put helmet and gloves in the top box, the key broke off in the lock. As i was 40mls away from home (and in England it illegal to ride without a Helmet) it was a problem. Luckily i got help from other bikers and we managed to break the lock. When i got home and took the lock off i kept the Eclip. I went on Ebay and mananged to get a replacement lock(barrel and two keys) for £8. When it arrived there was no new Eclip. This kind of clip should be readily available from any tool shop i would have thought, it is quite a common fastener.  

I had the same happen with my Givi top box, the point on the key where it enters the lock barrel was very narrow and it kept snapping. I drilled a very small hole in the opposite end of the barrel from where the key enters and each time it snapped I could push it out again. As I had side panniers with identical keys I took the barrels out and drilled them too.

Does anyone know size of circlip

Looks like a bog standard e-clip and has an OD of .450"

Thank you all for your help

jd 70 I went on google .Put Eclip on search. The site came up with diffrerent sizes of Eclip and some showed how to measure for a new clip.