Thank you both for your responses.
The staff are well trained, current and been with us for many years.
It's not a question of their ability to do the job correctly or safely. What bothers me is the fact that they have to operate purely on experience and on what the crew considers to be the correct procedure as far as lav. Service, potable water service, is concerned. Each crew member seems to have a different opinion on what the correct procedure is for the same type of a/c.
For a ground power things are a bit more standardized but again you have max outputs to consider depending on the type plus certain types that accept both AC & DC (had one last week), which of the two would be the preferred?.
Quite a few questions to which the answers are known and taken for granted, but the answers are based solely experience gathered from operating crews, engineers and not on what the manufacturers have advised.
With the big boys (Boeing & Airbus) the info on the above is readily available. This doesn’t seem to be to case with the likes of Gulfstream, Embraer & Bombardier (exec. Side of the market) , Cessna etc.
Had a look at “.. aircraft airport characteristics” on Google but the info is not in there.