Don,
The short answer to access to the keel is - you can't.
I am just starting my fourth season and have not renewed the anti-fouling om the keel at all. I have this week taken the cover plate of from the coach roof to check the mechanism and shackles inside. I have also replaced the rope used to raise the keel (Recommended to be replaced every two years). I don't seam to be having any fouling on the keel or indeed under the hull, only about a foot or so around the water line. I do regularly raise and lower the keel during the season. So far it all seams quite clean and slides ok.
I think after this season I will either ask Parkers to extract the keel and give it a good sort out, or try to establish a way of lifting it out myself.
One problem is that the keel is housed at an angle, so although it should lift straight out, it is straight out at an angle of about 15 deg. It makes it a bit more of a tricky lift out. A sturdy 4x2 timber frame work may be the answer.
Parkers are almost on-route between Rutland Water and our home, only about half an hour detour, so it might be easier to just let them sort it.
Graham Ebb
235/25 Blue Jazz