Broke out these covers, and replaced with some decent ones. One was on a ramp, which was a bit of a challenge I thought it was the last day of a nightmare job, but got home, 5 hours through the snow, and found I have to go back and put the same vinyl in the lift car.
Broke the old ones out, and stripped back the slab. Then closed up the size a little, with some 18mm Marine, to suit the new covers. If there were no time restraints, the square one would have been full size. Set the new covers in on packers, flexied in, then ardurapid infill all around. Latex to suit height, then vinyl up. Done quite a few of them now, there easy enough once you know what to do. But a bit smelly !!
