Nick,
I am not meaning to get nasty here, but i can't let you get away with your waffle.. It doesn't matter how long your family have been dashing, or what academic knowledge of materials etc you have. I have looked at the "types of finishes" section on your website, and would say the quality, (going by the pics) is no better or no worse than you would find anywhere up and down the country.
As a matter of fact, the finish on the gable end in the penultimate picture (lime stone) has a definite visible line/join right across the gable wall. It starts on the left, about a ft below the first bracket on the downpipe, and arcs it's way across the wall to the bottom left of the top window in the gable end.
From the other side of the window, it continues across the wall. The beginning of it is also visible in the final pic. You don't even have to zoom in to see it. As a plasterer Nick,, i was doing roughcasting before your arse was the size of a shirt button,,, most if not all of the real "plasterers" that i know or knew, could roughcast/dash.
They can also do different types of plastering, screed floors, (sand and cement or granolithic,), granolithic work in general, render, tyrolean, tiling, etc etc. Don't ever asume that because you, as a person/firm that specialises in "one area" of this trade, knows it all, nobody does,,,,, other pebbledashing websites out there say they are the best too, it's obvious. Whether you believe pebble-dashing is an art form or not, and even with your degree,, many a plasterer or builder, (a lot of them can dash too), would give you a good run for your money.
And finally,, there are more plasterers out there that can roughcast extremely well,, than there are roughcasters that can plaster.
Roughcaster.