Apologies for not taking any earlier part in this discussion. I haven't looked at the forum for weeks. I've seen Jaunty afloat in Poole Harbour, I'm sure, so hope to see her back there one day. Just a few points to add.
The angling of the rudder blade forward came about through my experience. The original blade was vertical and had a boarding step cut into it a la BR20. It had very heavy weather helm. I raised this with Matt and he had already had the idea of angling the blade forward to balance it. He made me a new blade and it was transformational. The problem with grounding though, is quite serious. If the blade is grounded, there is no way you can pull it up. If I get stuck like this, I have to start the motor to move forward with the blade uncleated. I have also freed it by uncleating the blade and then pulling forward on the anchor chain. You really don't want to settle on an extended blade on a falling tide.
The original paint on my boat was just single pack Toplac. It is good, but I am forever scraping and bumping my boat so I repaint her pretty well every winter. When I changed her colour from green to blue, I switched over to using Dukux weathershield, which i have found to be just as satisfactory. I have neither the time nor inclination to use any complex paint system. I need to touch up too often. On the bare timber, I've used all sorts of finishes and have settled on simple Danish oil. It is long lasting, very simple to apply and I can use it on my kitchen worktops.
The forward access hatches to the ballast tank still leak, even though I have removed the original screwed down hatches and replaced them with sealed down plywood disks. I don't know what the problem is.
The major weak point over the years is the stern part of the site decks in the cockpit. These are too thin. Both sides have cracked several times. I've decided this coming winter I am going to sand the whole deck back to bare wood and apply two layers of fibreglass. I'm going to fit new access hatches to the buoyancy tanks on their vertical sides and fill in the original deck hatches before I apply the fibreglass. This may just be a problem with my boat as I know Matt was doing everything he could to get the weight under 450kg, and possibly overdid it in this area!
I must say, I was delighted to see what the current price of a BC20 is...