I'll state right away that this IS an opinion -
In excess of 857 pounds sterling ($1200+) for a front mech, has to be one of the most ridiculous auctions on e-bay yet. This must hold the record for the single greatest price ever bid for a component. At that price, you could have an engineering company manufacture an identical one for half that - complete with fake patina.
Sort of makes you wonder if the auction isn't some kind of scam / sting - I mean to say just how many of those on the CR list would actually want to pay that for it if they could afford it ?
I'm sorry if anyones offended by this, but if you would pay that, you need to get out and ride some and perhaps take time to consider just how rare that "only produced for two years" derailleur is. In anyones language these prices, if in fact they are real, don't help anyone.
Good luck to the seller it certainly makes me wish I had one to sell, and the audacity to rip someone off comprehensively.
Bob Reid
Stonehaven
Scotland