Went last year on a two day stop off on the way to the vendee.
Outdoor pool(daughter said was quite cool, we were watching from the bar terrace) , play areas, bouncy castle and large trampoline for children. Bar and snack bar/take away.
We had a nice time although some of the pitches are shady.
Didn't explore surrounding area as we were resting before the next leg of the journey.
Going again this year as a stop off as well, about 1 1/2 hr drive away after you get off the tunnel.
Hope this helps you out a bit.
We stayed there for two nights last year on the way back to Boulogne. The site is well equiped with water on every site, adults and childrens pools, hot tub, by late August the trampoline mentioned above had bitten the dust, the owners spoke good English, most of the people there were Brits. We would probably book again if we were sailing to Boulogne but Dunkirk seems more likely this year. We enjoyed a day out at Mers les Bains, morning on the market then picnic on the pebbled beach. Only problem was a few of the pitches became waterlogged in heavy rain.
Don't forget to leave a review of the French and other European campsites you have visited!