If you can afford them then the Admiralty Tough Charts are very good. They offer good coverage of the Solent and some parts of the East Coast and are as tough and waterproof as they say. Thus there is no need for complex methods of waterproofing or chart cases. Not cheap, but I feel worth the cost for dinghy sailing in a Wayfarer if you are a regular to the areas. Beyond that I believe the Imray charts also do a water resistant version. Not as tough but still good – I have used them in Scotland.