https://en.wikipedia.org/wiki/Sodium_hypochlorite
20 ltres of 14-15% Sodium hypochlorite can go a long way and is ideal for mixing with soap to wash plastics, hard surfaces etc
One large concrete paving jobs I used 6 x 20 litres and the areas came up a treat without the need to use a pressure washer mixed 1-1 ratio. For plastics I tend to use a weaker mix.
whats hypo
I would suggest hypo is NOT to be used on uPVC:
http://www.anglianhome.co.uk/goodtobehome/guides/how-to-clean-upvc/#.VaE8wbuh3T4Using hypo on uPVC is quick, however it is not the solution to a professional job. In addition to possibly damaging the uPVC (see link and do a search on Google) it can damage the seals in any pump used to apply it (whether that be a hand sprayer or a pump such as those on wfp trolleys - I checked with the Shurflo supplier Williamson Pumps some years ago). It tends to kill the algae but the dead cells remain as does any dirt unless brushed away. This results in apparently clean uPVC but with a "bed" onto which fresh growth can regrow quicker than if the surface was physically brushed cleaned (this gem of info observed from where someone had cleaned with this method compared where it had been brushed clean).
It's a matter of choice for the service deliverer and the customer. If they are price motivated and they are willing to take a chance on damage, or if the gutters soffits and fascias are old and/or in poor condition anyway, then hypo may be the way to go. Personally I would never clean this way.
The best way is to use a TFR which is safe on uPVC applied in dilute form via a sprayer, backpack or trolley, agitated by wfp brush then washed with either pure from the tank or if you have a Hozelock connector to your pole, the garden hose. I always use pure just because it's easier (my hose doesn't kink: the custies always do). The effect of this is spotless gutters soffits and brackets that stay clean longer as all surface debris in the form of dirt and algae is washed away.
I'm not having a pop at the OP but if the last pic with the vegetation removed is the final finish I wouldn't pay if I was the customer. Here's a before and after that I did using the method stated. On the other hand it may be a part-finished job.
I always tell the customer that there is "good enough" (that is usually the result if they do it themselves, with the inside of brackets still dirty and dirt behind the gutter) or, if you are paying "as good as can possibly be achieved - sometimes showroom, sometimes just clean".