After a lot of thought and designing I finally built a lifting hardstand for my RL28 that I thought may be of interest to others contemplating getting their boat off their trailers for maintenance.
It has proved very safe and stable and allows the boat to be raised between 0.2m and 1.2m from the ground.
I have made a video detailing the construction and use of the stand for anyone who is interested.
Thanks John. The wobble rollers attached to the front lifting beam where not really needed in the end. I had them lowered a lot of the time and stability of the boat was still excellent. The lifting beams are the material commonly sold for landscaping retaining walls.