where can I find a travelling/camping/adventure equipment type shop in The Netherlands?

basically an equivalent of www.millets.co.uk.

Thanks

www.ilse.nl is a dutch search engine. Look for dutch camping related words, even use an online english to dutch translator site to help you.
Camperen is dutch for camping, avontuur is adventure, reizen is travelling. Hope this helps.

The equivalent of millets - well there are some small specialist retailers (but then not on the same scale as Millets and usually more expensive as they are specialists).

However I would say that it is best to go for one of the largest sports stores such as Perry Sport. In the stores I have visited, then they have this kind of gear (usually upstairs) Indeed, if you look at their website now, then they have tents on special offer http://www.perrysport.nl/ Here are the details for the one in Den Haag http://www.perrysport.nl/index.asp?strPageType=winkel&intWinkelID=14

As I do not know millet, being Dutch, I can only guess at their range.
But the biggest chain I know for outdoor sport activities in the Netherlands are Beverzwerfsport: http://www.bever.nl/
Shops in each mayor town, I do not know if they do also sell through internet, but search their site.
One of their shops is very close to den Haag HS, just 5 minutes walk.

There are many more dedicated outdoor sports shops, but as Bla bla said, most are very expensive, if good quality.

By the way, Dutch for camping is Kamperen, with a k, not a c.