The best sailors start in dinghies. Try a couple of local dinghy clubs (RYA website will give a list of ones local to you) and go with the friendliest. Typically it's a couple of weekends and then you will have enough of the basics to spend a summer pootling around on the club lake (most clubs now have a few boats to hire for minimal cost to members). After that you'll have enough connections to find a boat and know enough about what you want. Racing is the best way to improve your sailing.
Nice to hear about Rockley Point - it's where I keep my boat.
Ride it or milk it!