We used to do granolithic and rendered skirting years ago. Mostly up the sides of solid treads and risers on staircases, and around each wall of the landings,,,, I've never seen them used in houses, always wooden skirting.
I don't know whether a hard "external polyfilla" might work, to fill up the chips and knocks. I'd give it a go. I wouldn't use sand and cement,,,, the filler is a much finer texture, and probably made for this type of job. If,, it's going to be painted afterwards,, you'll never notice it.
We used to do loads of grano too, get it all in quick and then wait for it to take a rub, out on crawlers with six inch nails in them, trowellingg up bin stores the next day in winter . I seem to remember you could make a days' wages with 15 or 20 m2 (would that be right?) skirtings were a lovely number, used grano dust for them.........
That's right Mic', get it laid as quick and early as possible, let any water come up, then spend the rest of the day floating it over, and over again,,, then late in the day, the surface finally turns into a beautiful rich cream, ready for troweling, and as the grano floor surface got near to the final pass, we used to throw a few handfuls of carborundum dust over the surface itself, then trowel it in, to make it non slip. The floor surface was also kept wet for a few days after, to help slow the cure.
Also,, after the floor itself had set and cured, we would then fix our wall battens for the skirting, scratch coat the skirting out half way, then a day or two later, coat the grano skirting out to the full thickness of the batten, fixed around bottom of the walls, then when ready, work at it,, float it over/trowel it over to a smooth finish.
A few days later,, again using a grano dust mix, we'd run a small, neat grano coving all around the room, at the junction where the grano skirting met the grano floor. We'd run the grano coving, using a tea spoon as the tool. It gave the cove its shape, which provided a neat finish to the floor,, plus, with no sharp internal corners, it was easily mopped/cleaned. We also put a cove around all the treads and risers on grano screeded steps/stairs. I haven't done any grano work for a long time now,, although i suppose it would still be carried out on many jobs/contracts. The most nerve racking part of the job, a day or two after the g/skirting was finished,, was removing the guide battens along the top of the skirting,,, without chipping/damaging the finished g/skirting itself. The top square edge of the skirting was rubbed gently all the way along, with a fine carborundum stone, just enough to take the square edge off of it, and the flat top itself had a fine render rubbed in, to give a uniformed finish all the way along the top. A lot of work overall.
