Couple of engine lifts will lift it off the trailer and being a Witch is solid enough that you can lay it on its side . On a bit of carpet if you worried about the paint.
I bought a couple of tie down straps with ratchets that could handle 2500kg and then hung the boat from the top of shed supports creating a cradle. You can see one of the straps at the front by the bow. This would slide back just in front of the keel and there was another one just behind the keel. Had it hanging there for painting, obviously couldn't get on board when it was hanging.