This has been planned for a while, but delayed by brackets'' and legs'' mounting holes not aligning, plus weather etc.
Finally drilled and filed the work-hardened s/steel holes oval enough to match, found some strong plastic plant-pot saucers to stand the skew legs. When weather improves, cats may notice...
There''s a similar, but longer cleated ramp to replace the rotten compost bins the cats currently use to access the other wall.