Siblu is the new name for Haven Europe.
Unlike the UK sites I think most of the European sites are privately run and Siblu have caravans, reps and their own kids clubs along with other companies like Keycamp and Canvas holidays along side the sites own accomodation and pitches.
Some sites are big and busy and very similar to the Haven sites here, some are smaller and quieter. Most of the sites have their own websites so worth googling to have a look at that too.
Rules and regs around the pool and other parts of the sites are down to the site them selve and not Siblu so will vary from park to park and each country has its own rules. Like in Italy most pools require you to wear a bathing cap and trunks not shorts.
We were on a site in Spain, Cambrils. It was in April and the entertainment place was crammed at night but other areas quiet through the day. Lots of Brits as all the vans were rented to Brits, the Spainish rented the sites bungalows and the touring spaces had spainsh, germans and french, but was only 10% full. The site would be heaving in the summer if all accomodation and pitches were full, don't fancy that much. The entertainment (sites own) was tacky and amataur, the sites own kids club was fine but not secure area so I wouldn't leave young ones unattended. Restaurant was lovely, cafe was chips and all that but very nice food, but you were surrounded by video game machines and air hockey. Tennis and crazy golf expensive but well maintained.