lot of frustration here, some with specific suppliers.
For what it's worth, I've found City Bin to be pretty good, and their documentation and communications pretty clear (no affiliation, but a customer).
Some of the rules make sense once you think of the waste handling that has to happen at the sorting centre. Glass in the green bin will become shards of broken glass and a safety risk to anyone processing that waste. If someone really really wants to put glass in the bin, then I'm sure I could design you a machine to pulverise the glass to (more or less) sand and you could use it to amend your compostables, or use it to grit your footpath in the winter.
I've definitely, inadvertently, violated the rules though. e.g. putting stones and small quantities of rubble into black bin. Another angle is that some food packaging can have a recycling triangle with a line through it, as if it cannot be recycled, when in fact it often can be. They often take a lowest common denominator approach, but depending on the recycling operation they can process more/less materials.
Rubble reminds me of something a builder did to a family member's bin. He'd done work on a rental property, and had some cement left over. he dumped the unset cement into the black bin, filled it about a quarter. That's definitely not what's allowed (Certainly once set!) and makes bin very heavy indeed (so not a good idea to do that e.g. as an analogy of putting a brick in your toilet cistern

)
Also, I suppose it's obvious, but if any of you have kids and end up with a birthday party: be sure and put the helium balloons into the bin early, no matter how much crying it causes. As the helium leaks out of the balloon, the buoyancy effect naturally reduces, which will increase your waste charge (but I can confirm that nomatter how many balloons you throw out you can't get the "meter to run backwards")