friend has put this forward and having never been any comments if this is a decent place or not? we are in out late 30s so not a mad clubbing weekend just some good beers in some decent bars.
Well, it's probably a bit like planning a lads night out in Middlesborough or somewhere like that.
Places that aren't too far away but are much better would certainly be Köln or Düsseldorf, get down to the 'Altstadt' of either of those places and you'll have a good night
düsseldorf is good for a weekend, altstadt as said, hundreds of pubs there (it's called the longest bar in the world) or the hafen (harbour) area for trendier pubs and clubs
Cheap flights from Luton, they have a nice Christmas market, but is probably bettered elswhere. Could you time it with a Dortmund home game - which might be worth getting tickets for?