Thank you.
I think you summarized it well. I guess I can conclude that the bike was probably produced in 2000 with some modifications either requested by the buyer or done afterwards. Unfortunately, the series code does not help much and the catalog itself is not clear (and hard to read). I could not find a French version of the catalog and this UK one is actually posted on a French website.
The bike shown in the "australian" video is a Gold Team Special, also described in the 2000 catalog next to the Gold Race Team. It does describe SHIMANO shifters, but it is the SORA model, not TIAGRA.
Unfortunately, I could not open the link to the German FB post.
Have a nice day (it's already midnight here in Australia)
Stefano