I was at Munster last weekend for Pfingsten, I had a chat with the club sectary he said you would have to speak to the museum but didn’t see why not, at the rear of the museum there is a very large area aprox 15 x 70 meters along with a lake and river at one end and it may be possible to dig further obstacle’s though it would not be possible to combine the event on Pfingsten, it would be later or earlier, the attraction is obvious IF the museum allows such an event, Munster is located in northern Germany south of Hamburg but don’t mix it with Münster which is 200km away