In an ideal world that would be the answer Kev, apart from the Total cost, look at all the equipment you would have to carry, it would be possible for those with bigger vans, but those with smaller vans would find it a little harder.
Good comment Though
Very true about needing a large van. I have a box trailer that houses my generator, omnivac, extention leads, 40m of high pressure hose and a pressure washer and lances etc.
If I was doing domestic only and van space was an issue I would opt for the pressure lance, but for commercial this is a non starter for the reasons I mentioned above.
Also imagine trying to clean this with a pressure lance - what a mess that would cause. The picture is of a manual gutter clean we did but it will give you an idea of what to expect