I guess the thinking was ease of eurostar. as a group we've bbeen to spain, amsterdam, prague, talinn, ireland, hamburg, so just fancied summat different. The stag is a bit retiscent to go to eastern europe, so were looking at other avenues.
Someone else has already said it, but go to Belgium. Eurostar ticket to Brussels entitles you to free onward travel and Bruges, Antwerp or Ghent will adequately serve your needs. If bars with beer menus consisting of over 50-100 different brews sound like your kind of thing, then Belgium is your kind of place.
Alternatively, just all go down this bloke's local pub and get shit-faced. Never quite understood the modern need to inflict our mass piss-ups on the rest of the continent...