Tow Bar Replacement Part

I fitted a detachable tow bar on my Golf Mk IV a few years ago - pictures of the actual towbar etc are available on this guys site:

http://freespace.virgin.net/adrian.rose/golf4towbar.htm

I need to replace the red handled locking pin but VW say they do not sell it. They suggested it may be manufactured by Brink but Brink does not agree. I have searched the net to no avail as yet.

Can anyone tell me how to go about getting a replacement as I am unable to use my towbar and it is getting urgent - surely I do not need to fit an entire new towbar system...the part must be obrtainable!?

I know one of you geniuses will tell me what to do!!

Cheers.