I don't quite understand the phrase in bold: "This is a very high scoring wine from what will certainly prove to be in the top three vintages of all time," he said. "At the moment, we are talking to a lot of people about positions on Lafite because prices have come down so far it really looks like there is a very considerable upside."
In this context, a position is a financial term:
A position is the amount of a security, commodity or currency that is owned (a long position) or borrowed and then sold (a short position) by an individual, institution or dealer. A position can be profitable or unprofitable, depending on market movements. The practice of restating the value of a position based on its current value is called mark-to-market.
Recently the 2008 vintage produced a worldwide increase in price of over 125% in 6 months from release, which in turn has come to push some Asian countries to the top of the list of worldwide markets in which investment grade wine is purchased.
Buying wine and then selling it again six months later with a 125% increase would definitely count as a profitable position.
The jargon used here is that of financial investments.
In finance, a position is the amount of a stock or commodity that is owned. Lafite is the name of a famous fine wine. So, the person means.
"We are talking to a lot of people about purchasing an amount of the wine called Lafite as an investment (not to drink) because we think it is quite become cheaper recently, and has the potential to become much more valuable in the future"