'I can understand a client getting a bit impatient with the process.'
I dont......... more or less on every planning application form in the country are the imortal words ' Are there trees on or adjacent to the site'. Every developer knows, but some still choose to ignore, about BS5837 it's just they still think they can get away with it and that is why I take the blunt route by almost telling them off.
Education, education education it's a slow process but they will get there. I have had developers ask me to downgrade trees my answer is are they willing to pay me a life times worth of work when I get laughed at and ridiculed never to work in this industry again, no is the usual reply so hence my reply no and dont call me again your fired, I have done this several times in my career there are just some people who are not worth working for.
If developers get impatient they either do not know what they are doing or they are getting bad advice from their planning department/ agent. BS5837 has been around long enough now that ignorance is not an excuse, thankfully most are quite willing to have you on board and take your advice very seriously.