The ledge is wide enough and I am daft enough. Please be assured I am harnessed up and tied on. Polyurethane floor paint is being applied to the course of stone immediately below the tank in preparation for replacing the failed seal between the tank and the stone.
The new sealant will not adhere to stone unless it is first primed and sealed - hence the high level paint job.
This was a definite two man task - one doing the painting and the other seeing to safety and keeping up the supply of paint. Peter Bennett who took the picture did a splendid job on the latter tasks - to the extent that we were able to do a circuit of the tank ledge in just over an hour. I think we did three laps.
The removal of the failed sealant and its replacement will be trickier but when done the place will be a lot drier in driving rain.