Chris - myself and my family (wife and young daughter) stayed with this lot a few years ago and really enjoyed ourselves. For accommodation, they can organise self-catering up to high-end hotel ...and anything in between.
Some of good points
- less than an hour south of Athens (on island of Poros - yes it's spelt right, it's not Paros or Paxos!)
- Small, friendly, laidback island
- Watersports centre is very friendly and helpful (set you up a tab when you arrive so you don't need to carry cash around when you want food/drink from their outdoor (shaded) bar overlooking the centre and beautiful Neurion Bay
- Great laid-back instruction as often, or as little, as you like.
- Lovely little beaches close by, such as 'Love Cove' where you place your lounger on the sand in a few inches of water, don't have to move for drinks or snacks, and when it gets too hot you just roll over and you're in the Med!
- Lots of good restaurants locally
- Very child-friendly but in a way that you control, rather than activities being controlled for you in a complex
- Good base for sight-seeing, if you're than way inclined
- Good on price