Shop around first before going back to the dealer, there are companies out there (car supermarkets or importers, or even privetly) who are selling new cars or nearly new at reduced prices, there are bargains to be had, but possibly not with the exact same spec you're looking for. After you've done that, if you'd still rather buy from the main dealer, take the info on the other cars you've found with you, and you can use them as a bargaining tool, and if you show them that you're seriously committed to buying, and have the funds or finance in place, you should be able to get a deal (Also don't be afraid to tell them you're looking at other cars like the focus ST or the maybe even the seat cupra which is near enough the same car as the golf, only more powerfull and cheaper!).
Hope this helps.
g